Upgrading BGA components in a tablet? (it's a long 'un!)

[Starwright]

Hello everyone!

I've finally decided to register after lurking for a bit and try and overcome my fear of forums (long story short, I haven't had many good experiences on them so I don't bother to hang around. Anonymous people can be so cruel just because they can). Anyway, I'm hoping that i can get a bit on advice on what I consider a crazy (but cool) project. But since this is my first post, I'll tell you a little about myself and why I want to do this particular project. I apologise in advance for the long post that will follow, but please bear with me...

I'm a traditional artist with a love of drawing and sculpting. When I was little, I wanted to get into animation and have my own cartoons. As I grew older, video games became a large part of my life and then I thought about developing my own games or at least learning about computer animation (I ended up working as a games tester and that ended REALLY badly and I wasted 3 years of my life and several more after that, which leads me to now). In the end, I decided since what I sculpt actually looks like what it's supposed to, I would work on filming my own stop motion animations. I have recently built a manual desktop plastic injection moulding machine (just waiting on cartridge heaters from China for over a month now ) that I want to use to convert my clay sculpts into plastic articulated figures and keychains/charms to sell as i'm unemployed (I also cast in epoxy and polyurethane resins, metals and make silicone rubber moulds too).

I'm currently working on building a spincasting machine to use as a means of making detailed metal moulds for my plastic injection machine without the need of costly CNC machining. Hopefully it won't get too expensive as everything likes to be in the UK! OK, so I want to draw digitally to design packaging and also have some nice artwork up for my eventual website (or at least a blog), so I wanted a digital sketchpad of sorts. This is where the following comes in:

(Note: I'm going to copy and paste a rather long message I sent to someone about my project since they had a product I was planning to buy to help me out in the future, but everything still applies. I've cut out the bits relating to the person I was talking to, but he's apparently a member on these forums)

"It's true that I am working on learning more advanced electronics, but I also have a challenging project I want to complete. I want to purchase a Xiaomi Mi Pad 2 and upgrade its RAM, eMMC storage and processor:

http://xiaomi-mi.com/xiaomi-mi-pad-2/xiaomi-mi-pad-2-2gb16gb-pink/1

I've been in contact with Xiaomi about this (they ignored me) and I have also been researching on the components used so that I can ensure compatibility with whatever replacements I use. I've found a couple of teardowns and it seems that if I'm careful, I might be able to get the modules off easily with a hot air rework station since it's a single layer board (am I right about this?).

http://www.myfixguide.com/manual/xiaomi-mi-pad2-teardown/1

http://electronics360.globalspec.com/article/7408/teardown-xiaomi-mi-pad-21
(I've contacted the original website the teardown came from to see if they would let me have more info and images on just this specific tablet alone)

It seems it's also possible to install Windows 10 (what I want to do) on the Android version of the tablet (the 16GB one is the cheapest and also comes in the pink colour I want), but I don't know if I can do it with a blank eMMC (is there an EEPROM chip or something that holds the BIOS separate from the eMMC so they can be swapped with no complications and I just flash away? I have messed with Chinese tablets in the past. Heck, I'm selling one right now):

http://en.miui.com/thread-243286-1-1.html1

I'm hoping to get hold of 4GB of LPDDR3 RAM (2 x 2GB) minimum (though the Intel Atom X5-Z8500 can support up to 8GB of RAM) and upgrade the storage to 128GB. Finally, since they have the same "socket" and other similar specs, I want to replace the X5-Z8500 with an Intel Atom X7-Z8700 (would like to get a Z8750, but nowhere sells it as far as Google tells me. I can get the Z8700 from Mouser though, but I have another cheaper idea I'll mention later). This is only part of a goal I've been trying to achieve for years. I've wanted a compact digital drawing pad since I'm a traditional artist and I have been trying to migrate to digital media for ages.

I've tried Wacom's Intuos tablets, but can't get past the "disconnect". I can't afford the Cintiqs (even tried building my own and that failed. I used to frequent Bongofish.com as a member, but gave up) and the "penabled" tablet PCs have seriously bad parallax. I had a Samsung Galaxy Note 10.1 2014 that was almost perfect, but I just couldn't get used to Android on a tablet. I missed my full Windows programs too much. So I sold it recently. I thought about trying the "iPad" artist route, but with Windows 10 instead. Samsung has modified and rebranded the Wacom Intuos Creative Stylus 2 and turned it into the Samsung TabPro Pen, which is compatible with their TabPro S tablet. Which so happens to run Windows 10:

https://www.amazon.com/Samsung-Galaxy-Tabpro-Pen-EJ-PW700CBEGUJ/dp/B01G7FCYJG/ref=cm_cr_arp_d_product_top?ie=UTF8

I'm hoping that since it pairs with Bluetooth and the drivers are Windows 10 compatible, maybe someone will get it working with other tablets that have the criteria needed for a satisfactory inking experience. I'm willing to help in any way I can, but I need a decent little tablet first. So... yeah. That's my mission. I have a hot air rework station and suitable tacky flux (Amtech). I'm waiting on some leaded solder paste too (I only use lead solders, it's just so much easier to work with and I'm naturally a clean freak anyway with all the other materials I use). I just need to get the right equipment together and of course the components.

Micron (who has bought Elpida) have given me a useless response (basically ask Crucial, as if they know anything about BGA soldered RAM) and Intel and Samsung haven't responded to me yet, but I'm not expecting much from them. I was wondering if I could at least source the RAM a different way... are the modules soldered onto RAM sticks what I'm after in reality? They look like what I'm after, but I wouldn't know without seeing them in real life. I did think about buying a RAM stick and desoldering the chips off of them though for a start. I also thought about scouring eBay for faulty tablets that have the components I'm looking for as a cheaper way of obtaining the parts. The issue with that is how to test if the parts I want are still usable... Do you think what I'm trying to do is impossible? I think it's possible, just tricky. I've got a couple more items on eBay at the moment that I'm hoping will sell so I can fund this project."

And that's it. Do you think that I'm crazy to try this? Sure I could buy an 8" tablet that has a digitiser on its screen for pen/stylus input, but from what I've read on the internet from those that use them extensively, the latest offerings are pretty bad and stupidly expensive the level of bad they are. At least if I don't end up with the mini drawing tablet of my dreams, I might at least still have a cool little "ipad killer" to play with until a decent universal active stylus comes along. I'm more of a hands-on mechanical type person and while I can solder and repair stuff to an extent, I know very little when it comes to programming and ensuring FULL compatibility. I would love to design and populate my own miniature PCBs someday and have my figures light up with LEDs and even have animated dioramas using miniature motors(and of course more tiny LEDs!).

So now, I turn to you and the vast knowledge you all possess. Could you find it in your hearts to advise me on what I could do to make this happen successfully? While I know there are risks (safety and money wise as well as my sanity), I'm willing to take those risks to get what I want. I've always had the philosophy of "if you can't buy it, make it" and "if it's broken, try and fix it first before buying a new one"! Hope to hear from you all soon!

[JS]

I have a few questions...

First, why would you upgrade a pink tablet?
Second, why would you upgrade a windows tablet?
And third, why would you upgrade any tablet?
And while we are at it, does somebody uses a tablet?

  Leaving that aside, reworking BGA doesn't belong to the beginners forum, just no. If you are a beginner don't do it, if you are not a beginner and you are considering that as an exercise for rework this is not the place to ask. Also, to start working with BGA I'd probably recommend something else than a tablet, something more accesible to work with. I guess you wouldn't have much of a trouble taking the chips out with hot air, putting them back in is another story. Once you can do reworking with BGA chips I  guess it's your decision and you'll have the tools to decide if it's possible or worthy. Try some kit or any random PCB which uses a BGA, take some cheap working gadget, take the chip out, put it back in, starting with that kind of things I guess makes more sense than a tablet.

JS

[Starwright]

First, why would you upgrade a pink tablet?

The same reason some people have lime green or yellow cars and drive and maintain them. Just 'cause. And also so people who see it from afar don't come up to me asking how I got Windows to work on an iPad Mini. I mean, who's gonna mistake my little pink tablet for an iPad? Apple doesn't do pink anymore! Besides, I wanted the pink BECAUSE I don't want it to look exactly like an iPad (I'm a white/blue type of person myself though)!

Second, why would you upgrade a windows tablet?

People upgrade Windows PCs, right? Even old ones. So why not tablets? Besides, I like to get the most use out of a product as I don't have much money as it is. I don't need the latest and greatest, just what works for what I need it for.
 
And third, why would you upgrade any tablet?

Let's see, there are 3 choices for an answer here.
1. Why not?
2. So I can get close to the type of tablet I'm looking for.
3. The answer I gave to your previous question above also applies here.

And while we are at it, does somebody uses a tablet?

Considering many including the big name manufacturers are still churning out tablets to this day, I'd say "A lot more people than you think".

While I understand where you're coming from, I think it's a bit pessimistic to just say "don't do it, 'cause you're a beginner". I mean after all, we were all beginners at many of the things we've accomplished in life and if I took your advice and never tried, how would I get more proficient at it? I'm not that dense I would just jump straight in, I do have scrap boards to test on first! I was more hoping I could hear from the people who have done it (even just to replace a faulty part) and where they may have sourced their parts and learn any tips or pitfalls. YouTube videos can only get you so far. Because I am a beginner at BGA soldering, I started this thread here. Or is there a forum for "advanced stuff that beginners want to learn to do that are too advanced for the Beginners' forum 'cause some guy says so"?

I'm pretty sure if I posted this anywhere else I would get a generic "check out the posts in the Beginners' forum" reply. I've researched this beforehand and just really wanted some leads on where an individual can buy these specific components, but if I just asked that, I'm sure someone would ask "you know they're BGA soldered parts, right? What do you need them for?" So I got it all out in the open for ya. This is part of my research after all.

[wraper]

While I understand where you're coming from, I think it's a bit pessimistic to just say "don't do it, 'cause you're a beginner"

It would be way too optimistic even for professional. Nobody in sane mind would try to upgrade something by replacing BGA chip, yet in something like tablet. On top of that those BGAs most likely will be underfilled with epoxy what makes replacing 10x of PITA. And who said that replacing some chip would work at all, even if properly soldered. It is not plug and play like replacing PC hardware. And it's not like there are compatible replacements with better specs available . Best case you could get something like 3 GB ram instead of 2 GB given that you will hack the firmware first (which you won't). Or replacing eMMC (maybe will work if it is used for data storage only and not the firmware)

[rs20]

I suspect that this is an extremely ambitious project, and I suspect doing mechanical hacking to make a suitable SBC have the form factor you want will give a better result for less frustration. Nevertheless, if you were to forge ahead with modifying a tablet, I'd be asking:

Does the existing RAM in the tablet have a part number? Have you tried googling that part number? It's maybe possible that suitable chips are to be found on memory sticks, but that's most likely to be confirmed by seeing the suggested applications on the existing chip's datasheet. Once you have the part number, you can figure out the part number of a corresponding higher capacity chip, and then you have a specific part to find suppliers for. I'd focus on replacing RAM first, as it's the (strictly relatively speaking) least ambitious aspect of this plan.

Do you have any reason to believe that any of these upgrades will actually work? In particular, wouldn't the firmware know exactly what capacity of memory it's expecting to have, and simply fail to make use of any extra? PCs know how much memory they have installed by communicating with the DIMM modules via a protocol called SPD; a CPU talking to a plain chip has no such option. Unless the CPU tests various sizes of RAM every time it starts up (a seemingly convoluted and difficult step to implement to support a non-endorsed modification), I fear the most likely outcome is that you could install 8 GB of RAM and the tablet would work fine using only the bottom 2GB.

What does "seriously bad parallax" mean?

[Monkeh]

Just buy the Windows version of the tablet already. It even comes in pink.

[amyk]

Do you have any reason to believe that any of these upgrades will actually work? In particular, wouldn't the firmware know exactly what capacity of memory it's expecting to have, and simply fail to make use of any extra? PCs know how much memory they have installed by communicating with the DIMM modules via a protocol called SPD; a CPU talking to a plain chip has no such option. Unless the CPU tests various sizes of RAM every time it starts up (a seemingly convoluted and difficult step to implement to support a non-endorsed modification), I fear the most likely outcome is that you could install 8 GB of RAM and the tablet would work fine using only the bottom 2GB.

A lot of these cheap PC tablets are based on a stock reference design BIOS which might include RAM detection, it's easiest for Intel and the like to just release such a firmware image that the manufacturers can just flash onto their boards whatever the memory installed. It's also less likely that a company will go to the extra effort of removing such code and writing custom hardcoded RAM parameters when they have an image that works on all their board variants.

It seems it's also possible to install Windows 10 (what I want to do) on the Android version of the tablet (the 16GB one is the cheapest and also comes in the pink colour I want), but I don't know if I can do it with a blank eMMC (is there an EEPROM chip or something that holds the BIOS separate from the eMMC so they can be swapped with no complications and I just flash away?

I don't know about the newest tablets but I worked with some older ones which were basically a PC inside, so they did have separate BIOS and what they used for a disk, a CF card, was connected so that it looked like a normal HDD to the rest of the system. If these are also PC based, I suspect the arrangement to be similar, especially if it's a Windows system, but if it's more like a smartphone where everything is in one eMMC and the SoC directly boots from that, I would not be surprised either.

I agree with others that this could be very ambitious for a first project. Your best bet is to research as much as you can (including lots of datasheet-reading), and if you have some other electronics of little value with fine-pitch BGAs that you can practice on, that is also a good idea.

[iampoor]

Just buying a decent set of tools to do the rework would cost far more then what you would save....

As someone who always takes on overly ambitious project (and usually fails the first 5 times!  ) I would say this is WAY too ambitious for a beginner level project.
Watch some of Louis Rossmans video on youtube if you havent already. Might give a good idea of what tools you will need, and what the rework process look like.
This is not trivial work, even for professionals.

I dont want to be a downer, but I suspect (based on a few things in your OP) that you may not really understand how much work this will be. Of course, if you decide to go ahead and try, I will be cheering you on....in the very least, it will be entertaining. 

[JS]

  I'm not trying to bring you down, if you are doing this to get a cheaper better tablet I don''t think you will succeed, even if you succeed swapping the chips. Some of the reasons have been already mentioned, also is quite easy to ruin a chip or the entire board if one ball decided to go crazy and join the ball next to it, and there isn't just a matter of looking how nice your soldering skills are with a magnifying glass, you need X-ray to do that now. If you are doing this you have to know that the possibility exist that you expend a lot of money and time in it and end up without any tablet, I'm not hopping that happens to you, if you go for it I really hope you succeed and I'll be cheering you as well, but you need to know there is a chance of that happening.

  Excuse me, but this isn't a project for a beginner, if you are a beginner or not is another thing I can't discuss. If you say you are just starting with electronics I'd recommend run away from this, if you are just starting with BGA I'd say give it more time.

  The first 4Q were there cause I couldn't resist, I won't criticize your color choice or your OS choice (well, maybe the last one a little). The third one is something many people commented here, I sincerely don't think it does worth it, too much work for a few GB of ram, maybe changing the OS gives you the same speedup  . About the last one, I think the market is going towards better and bigger phones while tablets are less popular than a few years ago, starting to come factory with a keyboard then you have a netbook. There is still a market but I'm just saying it isn't what 5 years ago someone would expect it to be today. I like my life with a 5" in my pocket and my desktop, if an 8" tablet is all you need as a PC great! I'd like my 10" back to take my notes to classes but I wouldn't buy one now just for that and few other things.

JS

[Zbig]

About the last one, I think the market is going towards better and bigger phones while tablets are less popular than a few years ago, starting to come factory with a keyboard then you have a netbook. There is still a market but I'm just saying it isn't what 5 years ago someone would expect it to be today. I like my life with a 5" in my pocket and my desktop, if an 8" tablet is all you need as a PC great! I'd like my 10" back to take my notes to classes but I wouldn't buy one now just for that and few other things.

I noticed the recent trend to abandon tablets in favor of smartphones only usage too but, contrary to you, I don't get why is that. Have you used any tablet daily for some considerable time? There's a world's difference between browsing a webpage on 5" smartphone and 10" tablet. It's not about the features or processing power: the screen area alone is what makes this a different experience altogether. For me, the "just grab it from the coffee table like it was a newspaper and check stuff" use case alone justifies the existence of tablets. No laptop comes even close to that experience. My Sony Xperia Z2 Tablet isn't going anywhere soon, thank you very much. This, coming from a Lenovo Yoga 3 Pro owner, that was pretty much the state of the art in the area of PC convertibles just a year or so ago.

[JS]

the recent trend to abandon tablets in favor of smartphones only usage too but, contrary to you, I don't get why is that. Have you used any tablet daily for some considerable time? There's a world's difference between browsing a webpage on 5" smartphone and 10" tablet. It's not about the features or processing power: the screen area alone is what makes this a different experience altogether. For me, the "just grab it from the coffee table like it was a newspaper and check stuff" use case alone justifies the existence of tablets. No laptop comes even close to that experience. My Sony Xperia Z2 Tablet isn't going anywhere soon, thank you very much. This, coming from a Lenovo Yoga 3 Pro owner, that was pretty much the state of the art in the area of PC convertibles just a year or so ago.

  We are getting out of topic here, but you have to live with that in a forum. I did have a tablet all for myself (not one in the house or something like that) so I did live with one, 10" 2560x1440, so really nice display I do miss. I had it for more than a year till it died, I used every day and was my device for everything while traveling (which was a lot of time at that moment) and still the preferred device for gaming and reading school stuff at home. When it died I didn't miss it so much, I was just wandering to change the 4" phone for a 5"+ and it was what I was looking for. There are a few moments where I'd wish to have a few extra inches but overall I'm better with this, as more would be a problem to carry in the pocket, and having an extra device to carry around doesn't worth for me. To have a third device worth to carry it would need to be something like a macbook pro, with FW/thunderbolt capabilities, decent programing environment, etc. An android tablet (Or IOS) wouldn't do that for me, and I wouldn't even try to get back to W after more than a decade away from it. When the tablet died I had a 4" and a 13" macbook it used to stay in home, not long after I builded a desktop running OSX cause the 13" had 8 yo. so 22" at home and 4" on the road, the 13" served some help once in a while to help the 4".

  Still, for any use away from home I can live with 5" FHD. At home I have now a 39" TV hanging of the wall where I have my desktop connected, so, while having the coffee I do have where to look my morning stuff other than the phone.

  It's funny to look at my father with the macbook, the iPad and the iPhone messing around and swapping 4 times of device (key locked and all) to do anything while sitting in his living-room. It isn't funny when I'm expecting an answer of something depending on that. I'm one of those who won't get a new tablet any time soon.

JS

[Kilrah]

Apple doesn't do pink anymore!

Yup they do, they jsut call it "rose gold"!

But yeah, on one side saying you can't afford the proper model, but on the other wanting to get into something that requires buying equipment and parts that will likely cost more than said proper model, with a very high risk of being for nothing and for it all to end up as a pile of destroyed garbage doesn't really check out.

As said even if you were to master the hardware swap it is still quite unlikely it would actually work on the software side.

Also note that the Samsung pen will NOT give you anywhere close to the performance you'd expect of a proper graphic tablet, that requries specific hardware under the display.

[viperidae]

I wouldn't even try to upgrade a tablet. The PCB may not even have the extra address line required for doubling the RAM.
There's also the previous issues mentioned already:

• SPD that tells the memory controller the timing and size of the RAM is separate to the memory chip. It may be a EEPROM, it may be hard coded in the BIOS.
• The chip could be epoxied to the board to increase reliability
• You won't be able to heat the board from the bottom to get the chip off, it will be covered in bypass caps.
• The CPU in there now is a UTFCBGA1380 package. The balls are as close as 0.4mm and there's 1380 of them. The Z8750 and Z8500 are probably pin compatible though.

Upgrading the eMMC chip could work though, providing you can format it correctly and copy the data from the old one to the new one.

Have you seen the PCB of this tablet? It might have metal cans of heatsinks covering the chips
http://www.myfixguide.com/manual/wp-content/uploads/2015/12/Xiaomi-Mi-Pad2-Teardown-16.jpg
You can't physically get the RAM chips out without removing the metal can.