[Updated (3) 10th June] Raspberry Pi 400 - Quality Control problems?

[eti]

Before you read my documentation, know that I am not alone, as seen here:




~~~ I have received feedback from the lead designer of the Pi 400 ~~~
---> https://www.raspberrypi.org/forums/viewtopic.php?f=140&t=313386

I've just received a Raspberry Pi 400 (USA version) to review. Off the bat, I can tell you things about it which I can't, for the life of me, fathom:

#1 The keyboard flex and "feel" - the KB demonstrates significant flex, and a kind of "clacky", hollow sound/feel when typing on it. Bear that in mind, I shall pick up on it again at the end.


#2 The rubber feet number only two - the front "feet" are moulded plastic mounds, as common with a few other similar products. The rubber used for the back feet is not grippy enough; I feel they would have been wiser to use high grip rubber, such as silicone, or other product (TPU?) - think of the rubber used on older "ThinkPad" or HP "ProBook" machines (namely my ProBook 6460b, which, when on a desk, a wild horse couldn't drag off! MEGA high gripping friction!)

#3 The micro HDMI ports:
 
~ The where/why these are used has been done to death, it's daft, but I'll skip over that - the fact is, they managed to label pins #1 and #40 of the GPIO header (moulded in labels on the casing), so why not label the main HDMI "HDMI (primary, for single monitors)" or similar? One would assume that HDMI port #1 would be the one on the left as you sit at the unit, ports facing away from you... nooope... I sat there for a few mins wondering why I got no video (okay, partial PEBKAC, but ya know... sort it out guys!)

Okay so back to the keyboard flex/hollow sound & feel:

I took mine apart - a VERY simple affair with a plastic pick, unclipped the two-part (upper and lower) housing, lifted the keyboard upper part, and was greeted by a 26 pin membrane ribbon cable which has "3M" double-sided tape on it, the other side stuck to the cable, CLEARLY meant to stick the ribbon down to the steel keyboard backplate, but the brown backing paper is intact, and the ribbon IS NOT stuck down.

Also of note, three or four heat-staked plastic "rivets" which hold the steel keyboard backplate to the plastic, had ALREADY broken off (I've used the machine TWICE, it's brand new). They are clearly cheaping out on the keyboard assy mfr - I am not sure how much I believe the whole "Made in UK"  thing, as the keyboard is obviously made El-Chinarado, and has a Chinese label on it. Fair enough, but HOW cheap do you need to go?

What is UTTERLY baffling, however, is the missed opportunity of having the keyboard assembly backplate and the large (2mm?) thick aluminium sheet which is a huge heatsink, in SUCH close proximity - parallel to each other across the width and height of the internal dims of the machine, and yet... THERE IS A GAP, a void between them, so that the keyboard is UNsupported apart from the edge of the mouldings where they clip together - this means the the typing experience is "okay-ish" but hollow, and the best word I can use is "clacky" - plasticky.

Whilst inside, I added strategically  placed blobs of "White Tack" across the heatsink plate (the thing barely breaks a sweat, so heat is no issue) as a test analogue for some form of high density foam or rubber which I have to find, and ensured each blob was around 5mm high, and then clipped the two halves back together, and then pressed firmly and uniformly across the keyboard, to ensure the "White Tack" had settled and reached a level. The reason for this is to allow the heatsink plate to act as a support for the KB - which works!

... the sound and typing feel are almost NIGHT AND DAY! The "White Tack" absorbs resonance and "clacky" sounds, and transfers the typing load onto the heatsink plate. It's not as if I covered the ENTIRE heatsink in it, or in foam, just at "strategic" points (Okay, I winged it  )

Why would they MISS OUT such an obvious, EXTREMELY cheap (moreso in bulk!) mitigation? Clearly their QC is lacking, I feel. I have attached my photos and audio files (where I compare the sound)

The complaints about the heat-staked "rivets" on the backplate, I have seen elsewhere also. No one seems to have mentioned the HDMI ports not being labelled. I am not sure why they wouldn't do that.












UPDATE:

I have (semi-temporarily) laid "Sellotape" strips on the heatsink, sliced up a "3M" self-adhesive foam pad into little slices (around 20 I think) and stuck them at strategic locations ON TOP of the "Sellotape". My adding the "Selloptape" is to allow me to remove this arrangement, the fact being that consumer sticky tape is infinitely easier to lift off than "3M" MEGA grade, will-hold-an-elephant adhesive!

The result is a MUCH firmer, more solid typing experience with little if any "clackiness" or hollowness in the key feel. Also, these foam pads are very dense (closed-cell foam I'd think), and will likely reduce the chance of the heat-staked plastic "rivets" breaking off, to low or nil.

I see no bowing of the keyboard across its width (looking across from the right end, eye aligned with the surface) and I see only a VERY slight curvature from the bottom to the top edge of the keyboard, but that may be by design anyway. I hope this helps people, it sure makes typing a whole lot more enjoyable (I am hyper sensitive across all my human senses and perception, being able to still hear 18Khz sounds at the young age of 46!)

There is a concave recess where the heatsink plate is formed to contact the SoC, which I didn't add pads to - it seems redundant and a little pedantic to do so, and also I am unsure about how transmitting force directly down on the SoC, via that area of the heatsink, would affect the SoC.

Photos of the mod: https://photos.app.goo.gl/QTnaBuDibfpBTsoD6

[DiTBho]

My experience: bought three units, returned one.

Always check it when you get from amazon, I mean before packaging it as a gift item 

(the two units were gifts for two my best friends)

[janoc]

While what you are saying are certainly valid complaints, you do realize you are complaining about the "feel" and quality of a $100 computer, right?

The last time a complete computer was sold for that price, we got ZX Spectrum - and the design compromises on that are legendary. OK, not completely comparable, different era, but the point is that this is built down to a price, with cheap off-the-shelf components (like the chiclet keyboard), so that kids can bang this around for a bit and it will be cheap to replace/repair when they break it.

For a more serious use you would be better off just buying RPi3/4, stick it into a nice cooled/ventilated case and use an external keyboard instead.

That said, feel free to send your improvements to the Foundation, I am sure they will be happy (no seriously) to have them and may even incorporate the feedback into the next revision of the product. They are known to listen to their customers.

[ebastler]

My experience: bought three units, returned one.
(the two units were gifts for two my best friends)

You got rid of yours, but imposed two onto your friends? 

[Nominal Animal]

Looks like you could easily cast some blobbets in low-durometer (aka soft) silicon, and just plop them in place for the same effect.  Cost is minimal, and with a suitable hardness (pretty soft, if you use say a dozen of them), results should be at least as good as you got with white-tack.

It would be interesting to see if soft adhesive silicon shock absorbers (meant for cupboard doors and such) have the right dimensions.  They're easily available in about a standard size at brick-and-mortar stores, eBay, Amazon, etc.  The ones I have (a set of 100 in a sheet) are very uniform, 8mm (0.31") in diameter, 2.5mm (0.1") in height, but I suspect they're too hard: a single one is enough to absorb the "bang" when throwing a cupboard door closed.

I often use gasket silicone (or whatever non-acid curing, usually platinum curing silicone putty; medical grade low-durometer is best, but kinda expensive) for similar purposes, from standoffs to vibration absorbers between chassis elements.

That said, feel free to send your improvements to the Foundation, I am sure they will be happy (no seriously) to have them and may even incorporate the feedback into the next revision of the product. They are known to listen to their customers.

As long as you do not mention anything Open Source, or the FOSS/Libre Software Movement, or indicate such preferences.  They really, really don't like that.

[eti]

While what you are saying are certainly valid complaints, you do realize you are complaining about the "feel" and quality of a $100 computer, right?

The last time a complete computer was sold for that price, we got ZX Spectrum - and the design compromises on that are legendary. OK, not completely comparable, different era, but the point is that this is built down to a price, with cheap off-the-shelf components (like the chiclet keyboard), so that kids can bang this around for a bit and it will be cheap to replace/repair when they break it.

For a more serious use you would be better off just buying RPi3/4, stick it into a nice cooled/ventilated case and use an external instead.

That said, feel free to send your improvements to the Foundation, I am sure they will be happy (no seriously) to have them and may even incorporate the feedback into the next revision of the product. They are known to listen to their customers.

It's this kind of "ehhh, it's good enough" attitude that allows companies to  crow about the virtues of their products and how amazing they are, whilst simultaneously getting away with junk as a result  of corner-cutting, knowing that the "community" will make excuses for them until the cows come home (people become indoctrinated and institutionalised - SERIOUSLY) , because the company has endeared people to them by churning out stuff they can afford, and feel they have "no right to complain because it's cheap"  - just because something is affordable, doesn't mean it shouldn't be FIT for the purpose you bought it for. Imagine "the foundation" mentioned all these flaws in their marketing material - I supposed you'd just nod your head and smile, and happily hand over your $100, right? Wrong.

Regardless of price, a product should be FIT for the purpose for which it is produced, otherwise, why even bother making it? The fact it's cheap in PRICE just doesn't justify picking inferiior parts and chancing your arm as a company, and adopting a denialist attitude (backed up by "the community") when people raise VALID COMPLAINTS. Why are people like this, defending poor quality? Because it's a throwaway society, and they'll just buy another product, so their wasted money doesn't seem such a big loss.

Buy cheap, buy twice, but in this case there's no choice of alternative.

Your comments don't negate my observations. This thing NEEDS fixing, along with the rubber "feet" which are all but a token gesture, not being nearly grippy enough. Saying "If you don't like it don't buy it, buy a Pi 4 and..." is whitewashing over the point - THIS IS A PRODUCT, AND IT *IS* BEING SOLD, AND IT HAS FLAWS... the keyboard is appalling quality, so much so that in my teardown, a few rivets had ALREADY come off after TWO brief periods of use (and I tap the keys gently, I do not hammer them like a caveman).

Now let's see a school buying 500 of these, and allow a year to pass... let's see how well they hold up to abuse from children (that is, after all, one use case towards which these are aimed)

Lest we forget, "the foundation" being a charity does not mean they're four people working out of someone's garage, the wives bringing sandwiches and cups of tea out to them at lunchtime. This is A COMPANY who've sold many, many MILLIONS of devices worldwide - regardless of unit price, less slack should be cut than IS. People defending junk will ensure you always get junk, and the people selling it become complacent with regard to correcting the flaws, since "the community" will defend their pet to the end (indoctrination, as with all internet "communities", a few fringe outliers spend SO LONG online, knee-deep in their pet device and "the community" which surrounds it, they have trouble stepping outside and seeing the woods for the trees as a normal person would, objectively)


If something is crap, I will say so, and not pretend it ain't or justify it away.

[eti]

My experience: bought three units, returned one.
(the two units were gifts for two my best friends)

You got rid of yours, but imposed two onto your friends? 

[janoc]

As long as you do not mention anything Open Source, or the FOSS/Libre Software Movement, or indicate such preferences.  They really, really don't like that.

Don't troll. You know as well as anyone that they can't open source what they don't own - aka things related to the Broadcom SoC. And everything else is pretty much open already.

[janoc]

While what you are saying are certainly valid complaints, you do realize you are complaining about the "feel" and quality of a $100 computer, right?

The last time a complete computer was sold for that price, we got ZX Spectrum - and the design compromises on that are legendary. OK, not completely comparable, different era, but the point is that this is built down to a price, with cheap off-the-shelf components (like the chiclet keyboard), so that kids can bang this around for a bit and it will be cheap to replace/repair when they break it.

For a more serious use you would be better off just buying RPi3/4, stick it into a nice cooled/ventilated case and use an external instead.

That said, feel free to send your improvements to the Foundation, I am sure they will be happy (no seriously) to have them and may even incorporate the feedback into the next revision of the product. They are known to listen to their customers.

It's this kind of "ehhh, it's good enough" attitude that allows companies to  crow about the virtues of their products and how amazing they are, whilst simultaneously getting away with junk as a result  of corner-cutting, knowing that the "community" will make excuses for them until the cows come home (people become indoctrinated and institutionalised - SERIOUSLY) , because the company has endeared people to them by churning out stuff they can afford, and feel they have "no right to complain because it's cheap"  - just because something is affordable, doesn't mean it shouldn't be FIT for the purpose you bought it for. Imagine "the foundation" mentioned all these flaws in their marketing material - I supposed you'd just nod your head and smile, and happily hand over your $100, right? Wrong.

Regardless of price, a product should be FIT for the purpose for which it is produced, otherwise, why even bother making it? The fact it's cheap in PRICE just doesn't justify picking inferiior parts and chancing your arm as a company, and adopting a denialist attitude (backed up by "the community") when people raise VALID COMPLAINTS. Why are people like this, defending poor quality? Because it's a throwaway society, and they'll just buy another product, so their wasted money doesn't seem such a big loss.

Buy cheap, buy twice, but in this case there's no choice of alternative.

Your comments don't negate my observations. This thing NEEDS fixing, along with the rubber "feet" which are all but a token gesture, not being nearly grippy enough. Saying "If you don't like it don't buy it, buy a Pi 4 and..." is whitewashing over the point - THIS IS A PRODUCT, AND IT *IS* BEING SOLD, AND IT HAS FLAWS... the keyboard is appalling quality, so much so that in my teardown, a few rivets had ALREADY come off after TWO brief periods of use (and I tap the keys gently, I do not hammer them like a caveman).

Now let's see a school buying 500 of these, and allow a year to pass... let's see how well they hold up to abuse from children (that is, after all, one use case towards which these are aimed)

Lest we forget, "the foundation" being a charity does not mean they're four people working out of someone's garage, the wives bringing sandwiches and cups of tea out to them at lunchtime. This is A COMPANY who've sold many, many MILLIONS of devices worldwide - regardless of unit price, less slack should be cut than IS. People defending junk will ensure you always get junk, and the people selling it become complacent with regard to correcting the flaws, since "the community" will defend their pet to the end (indoctrination, as with all internet "communities", a few fringe outliers spend SO LONG online, knee-deep in their pet device and "the community" which surrounds it, they have trouble stepping outside and seeing the woods for the trees as a normal person would, objectively)


If something is crap, I will say so, and not pretend it ain't or justify it away.

If you have instead of writing this (which is, btw, breaking into an open door - nobody is disputing that what you have found is a problem) sent an e-mail the RPi Foundation with the explanation of what you have found and how it can be fixed, you would have done much better.

All I am saying is that if you buy a $100 computer that is meant as a toy for kids, there are going to be compromises. If this is really all you have found and bothers you on that machine, I think they could congratulate themselves, because this is an easily fixable oversight.

The USB 3 port killing 2.4GHz wifi on these machines is a much worse problem ...

[Nominal Animal]

As long as you do not mention anything Open Source, or the FOSS/Libre Software Movement, or indicate such preferences.  They really, really don't like that.

Don't troll. You know as well as anyone that they can't open source what they don't own - aka things related to the Broadcom SoC. And everything else is pretty much open already.

Stop lying, will you?  Look this up.  You believing otherwise is worthless: facts are facts.

The attitude of the Raspberry Pi Foundation towards the open source projects they exploit is well documented by their lack of co-operation with said projects.  In the foundation, only the temporarily employed members ever interact with FOSS projects; the permanent technical personnel, and definitely the technical leads, never do.

In the Raspberry Pi forums, you will get a much better welcome and response, if your project is either educational or proprietary; optimally both, or public domain.

Go there and see for yourself, and stop propagating lies based on your own personal beliefs without any basis in fact.  The recommendation I gave is based on observed behaviour – and you accuse me of trolling?  You are a piece of work.  Oh well, one more addition to my ignore list.

[eti]

While what you are saying are certainly valid complaints, you do realize you are complaining about the "feel" and quality of a $100 computer, right?

The last time a complete computer was sold for that price, we got ZX Spectrum - and the design compromises on that are legendary. OK, not completely comparable, different era, but the point is that this is built down to a price, with cheap off-the-shelf components (like the chiclet keyboard), so that kids can bang this around for a bit and it will be cheap to replace/repair when they break it.

For a more serious use you would be better off just buying RPi3/4, stick it into a nice cooled/ventilated case and use an external instead.

That said, feel free to send your improvements to the Foundation, I am sure they will be happy (no seriously) to have them and may even incorporate the feedback into the next revision of the product. They are known to listen to their customers.

It's this kind of "ehhh, it's good enough" attitude that allows companies to  crow about the virtues of their products and how amazing they are, whilst simultaneously getting away with junk as a result  of corner-cutting, knowing that the "community" will make excuses for them until the cows come home (people become indoctrinated and institutionalised - SERIOUSLY) , because the company has endeared people to them by churning out stuff they can afford, and feel they have "no right to complain because it's cheap"  - just because something is affordable, doesn't mean it shouldn't be FIT for the purpose you bought it for. Imagine "the foundation" mentioned all these flaws in their marketing material - I supposed you'd just nod your head and smile, and happily hand over your $100, right? Wrong.

Regardless of price, a product should be FIT for the purpose for which it is produced, otherwise, why even bother making it? The fact it's cheap in PRICE just doesn't justify picking inferiior parts and chancing your arm as a company, and adopting a denialist attitude (backed up by "the community") when people raise VALID COMPLAINTS. Why are people like this, defending poor quality? Because it's a throwaway society, and they'll just buy another product, so their wasted money doesn't seem such a big loss.

Buy cheap, buy twice, but in this case there's no choice of alternative.

Your comments don't negate my observations. This thing NEEDS fixing, along with the rubber "feet" which are all but a token gesture, not being nearly grippy enough. Saying "If you don't like it don't buy it, buy a Pi 4 and..." is whitewashing over the point - THIS IS A PRODUCT, AND IT *IS* BEING SOLD, AND IT HAS FLAWS... the keyboard is appalling quality, so much so that in my teardown, a few rivets had ALREADY come off after TWO brief periods of use (and I tap the keys gently, I do not hammer them like a caveman).

Now let's see a school buying 500 of these, and allow a year to pass... let's see how well they hold up to abuse from children (that is, after all, one use case towards which these are aimed)

Lest we forget, "the foundation" being a charity does not mean they're four people working out of someone's garage, the wives bringing sandwiches and cups of tea out to them at lunchtime. This is A COMPANY who've sold many, many MILLIONS of devices worldwide - regardless of unit price, less slack should be cut than IS. People defending junk will ensure you always get junk, and the people selling it become complacent with regard to correcting the flaws, since "the community" will defend their pet to the end (indoctrination, as with all internet "communities", a few fringe outliers spend SO LONG online, knee-deep in their pet device and "the community" which surrounds it, they have trouble stepping outside and seeing the woods for the trees as a normal person would, objectively)


If something is crap, I will say so, and not pretend it ain't or justify it away.

If you have instead of writing this (which is, btw, breaking into an open door - nobody is disputing that what you have found is a problem) sent an e-mail the RPi Foundation with the explanation of what you have found and how it can be fixed, you would have done much better.

All I am saying is that if you buy a $100 computer that is meant as a toy for kids, there are going to be compromises. If this is really all you have found and bothers you on that machine, I think they could congratulate themselves, because this is an easily fixable oversight.

The USB 3 port killing 2.4GHz wifi on these machines is a much worse problem ...

~ Even if it were "a toy", and it isn't, I'd expect a toy to be built to a reasonable level of quality, and not fall apart (now imagine their reputation if it is sold as a "toy" and the keyboard isn't up to snuff - THE VERY THING which sets this product apart from their others), and it is weak and flimsy, poorly ... ahem ... "engineered", IE, BOM hammered down to the lowest possible price, and a Chinese supplier is more than happy to shift ANYTHING they can.

~ If I buy a loaf of bread for $0.50, and it has mould, I am still entitled for it to NOT have mould, and right to complain about it to the baker.


I despair when some folk will find "reasons" to defend ANYTHING, no matter what. The keyboard is naff quality, the rubber feet don't grip properly, the HDMI ports are NOT LABELLED... but aside from that it is marvellous,

Now I know what the people who complained about the Apple "butterfly" keyboard mechanism failing, must've felt like at the outset, when they were the first few to notice & complain. No one pays heed until the numbers are substantial, and later on IF AND WHEN the manufacturer OFFICIALLY acknowledges and rectifies the issue, openly and publicly (usually with self-congratulatory fanfare), the rest of the world SUDDENLY "validate" the complaint.

[DiTBho]

It's this kind of "ehhh, it's good enough" attitude that allows companies to  crow about the virtues of their products and how amazing they are, whilst simultaneously getting away with junk as a result  of corner-cutting, knowing that the "community" will make excuses for them until the cows come home

Yep, I do think the same! The RPI is the perfect example of this wrong kind of business.

* * *

RPI-v4 with 8Gbtye of ram
However, talking about RPI, I am more concerned about the new RPI-v4 with 8Gbtye of ram: Last week I bought four units for a project and returned everything to Amazon. Why? Because I have found that each card has some design mistakes on the LDO for which it sometimes shows unpredictable behaviors. Usually when the CPU and ram under heavy load (4 cores busy, 7 Gbytes in use) the frequency throttle unit does it job preventing the chip to burn due to over-temperature, but when the temperature is cold enough to allow more transistors to operate, they try to suck more peaks of current from the LDO, and since the component is inadequate, and worse still, there is no tank, the voltage drops below the critical level and bad unpredictable things happen on the software side.

ODYSSEY Intel Celeron J4125
In the end, my colleagues decided to replaced the four RPI-v4/8GB (90 Euro) with four ODYSSEY Intel Celeron J4125/8GB (198 Euro). Each node has 4-core @ 2.0 GHz CPU that burst up to 2.7 GHz, 8GB LPDDR4 RAM, and it didn't give us any bad surprises.

* * *

Jetson XavierNX Cluster
At the moment I am working with a Jetson Cluster for four Jetson Xavier NX units. It sucks a lot of current, and it's very loud, it looks like a heater that you use in winter days, and I think I can use the phrase 'costs an arm and leg' to describe something that is considered to be extremely expensive or excessively pricey: *** 2500 USD! *** It's for a machine learning experiment, not something you can call "hobby", and there are two colleagues sharing the repository.

I love the quality of the hardware, and also the quality of they quality control: no return, no defect, every single item (including cables, LOL  ) in the box has its "QC-passed" sticker on it.

OK, it may sounds "silly", do you really trust a "QC-passed" sticker? Well, never seen any sticker on RPIs

• RPI-v4, no "QC-passed" sticker -> 4 of 4 returned (defective LDO)
• RPI-400, no "QC-passed" sticker -> 1 of 3 returned (defective keyboard)
• ODYSSEY Intel Celeron J4125, "QC-passed" sticker -> 0 of 4 returned
• Jetson XavierNX Cluster, "QC-passed" sticker -> 0 of 5 returned (two XavierNX nodes + backplane)

and this kind of sticker, when they look something serious, it gives you that sure thing feeling that someone really checked before shipping 

[eti]

"It's affordable AND it's got community support - what else do you want, something which is actually designed competently? Go away, we hear complaints all the time and have to ignore most of them"

... is the general air of complacent contempt I feel from pi towers.


---> https://forums.theregister.com/forum/all/2021/03/15/pi_not_listing/

[CatalinaWOW]

Only one thing surprises me here.  It seems obvious that those plastic rivets were melted down manually, since I can't imagine how to make a machine do it so non-uniformly.  At the volume these are selling it is hard to understand why they haven't automated that step.  Even partial automation such as an appropriately shaped and heated press bar to do them all at once after manually assembling the components.
Labor can't be that cheap.

I suspect that the comment about using the heatsink as a support will be incorporated somewhere along the line.  When the molds wear out or something like that.  Same thing on the port labels, though that is already solved with an RTFM comment.

[eti]

... Same thing on the port labels, though that is already solved with an RTFM comment.

To which I would respond: "It might help you if you RTFM about product design, testing and mfring!"

How hard is it to label two ports: [HDMI 1 (primary)]     [HDMI 2 (secondary)]
Not hard at all, in fact by embossing them, it SAVES them plastic

[CatalinaWOW]

Sorry I offended you.  I am also glad you have never left off a simple feature or were so tight on money that the charge for engraving in the mold was an issue.  Sure over the production run the plastic savings will pay for it, but cash flow is a bitch sometimes.

[eti]

Sorry I offended you.  I am also glad you have never left off a simple feature or were so tight on money that the charge for engraving in the mold was an issue.  Sure over the production run the plastic savings will pay for it, but cash flow is a bitch sometimes.

“Offended” me? No you didn’t.

[DiTBho]

"It's affordable AND it's got community support - what else do you want, something which is actually designed competently? Go away, we hear complaints all the time and have to ignore most of them"

That person probably doesn't get that the *Community support* is offered by volunteers who offer their free time to assist people. It is literally someone who cares to answer when you have a question to ask. The company cannot list it as offering a service, because in reality it only offers a forum, where other people do the support work!

... is the general air of complacent contempt I feel from pi towers.

What makes it even worse is that the R-Pi seems to really accept *** any error *** (like the LDO problem I mentioned above) without trying to go out and fix it, when they hear complaints, most of the time simply they ignore them.

[eti]

OP updated with a new mod 

[ebastler]

Thanks for also adding the link to the feedback you received in the Raspberry forum to the OP. Very interesting details from Simon there, the lead designer of the 400.

Just for the record here: There is not really much difference between the two HDMI ports, which is why they are not labelled individually. It does not matter which port you use to connect your (primary) display. What does matter is that the display is connected before you boot the Pi, so it can be detected during startup.

The documentation is actually quite clear regarding the "connect before turning on" part, but I have not seen an explicit note that the two ports are largely equivalent.