Removing/Decapping an epoxy blob

[NiHaoMike]

Photos attached for anyone who is interested.

Nothing has really changed, it's always been about accessing the data. That I can do easily, getting access to the NAND is the difficult part in this case.

I've pretty much decided that this is a dead end. It's not really going to be worth the time or effort for the data that is on it. Even if I managed to get access to the chip, there is no guarantee that its even intact or the data is readable.

I think the owner of this drive has learned a valuable lesson.

It looks like you can just remove the controller to gain access to the flash pins.

[amyk]

Remove controller, solder wires and connect to universal programmer. Should then be easy to tell if the flash itself is dead or not.

[Halcyon]

Web search brings up some production/debug tools for this controller and datasheets of similar parts so I think data recovery professionals may be able to help if the owner cares enough to fork out some $$$. Flash recovery seems to be a thing, I have seen ads.
Or you can try to DIY.
I don't understand your logic in decapping this damn thing. Everything needed to talk to it should already be brought out to that SOIC.

I've tried those tools, they don't recognise the NAND. The controller is working as it should.

Remove controller, solder wires and connect to universal programmer. Should then be easy to tell if the flash itself is dead or not.

Great idea. I'll give this a go.

[tsman]

I couldn't find the CBM2199 datasheet and the manufactuer even doesn't list it on their website. There is a datasheet for a larger CBM2098E and a list of compatible flash chips for the CBM2199 from 2017. It looks like the CBM2199 only supports 8-bit async NAND which makes it a bit easier.

If you do gain access to the contents of the flash chip, you'll still need to at least partially reverse engineer the controller wear leveling and ECC to make sense of it. This will then have the usual filesystem churn on top caused by the owner modifying files on the stick.

Give it a go but this person will have to accept that chances of success will be very low. If you do manage it then they owe you big time for the heroic data recovery efforts.

[magic]

I did an experiment with 99.5% "glacial" acetic acid. Here's the results after one week of submersion:

Aluminium foil: appears unaffected, still shiny.
Clear epoxy resin: fragile and brittle, easily broken with bare fingers.
Copper: appears unaffected although some attack must be taking place because the liquid turned cyan.
A piece of DIP package: well, here's where problems begin. I could break it but only maybe a tiny bit easier than before the acid and certainly not easily enough to confidently recover dies.

I dropped that piece of DIP back and will check it again after a month or two.

Meanwhile, I will probably experiment with heating that stuff. Per some chemical compatibility charts I found, epoxy is supposed to become more vulnerable to various carboxylic acids at elevated temperatures. Yes, acetic is flammable. I'll only use small quantity and some place where fire is no issue.

And before someone mentions nitric/sulfuric, it can only be bought illegally here for whatever reasons