[Galaxy Tab 2 Q&A, Help & Troubleshooting] BoneWithABeagle:
To reply the post you made in the CM12.1 dev thread here....

After tinkering around with the device and digging through the Intertubes...

If the eMMC chip in your device is on the list of known garbage (see CyanogenMod Wiki) - sorry, but Samsung clearly deserves no praise for shipping total crap - it is a pretty solid assumption to consider the eMMC being beyond repair once it bricked - unrelated to the device being a P31xx or a P51xx.

The ones listed as "data corruption" in the "Impact" column can possibly be resurrected by JTAG'ing the device to completely erase the chip, re-partition and re-flash. That being said ... the M8G2FA chip (which is listed as "data corruption" with Firmware 0x11 AND "erase bug" (read: "bricked beyond repair") with a unknown Firmware version) is a real oddball. If you look around you actually find out that this particular eMMC chip dates all the way back to the Samsung Galaxy S2 (the phone, which is a good bit older than the Tab 2 series) where it caused the very same problems. Chances are 50:50 to get it back to work by going down the full route (erase, re-partition, re-flash everything through a JTAG box). Just keep in mind it is a 50:50 chance, there's no guarantee it works (as a lot of forum posts around the Intertubes reinforce).

Replacing the chip is impossible. It is a SMD part... unless you have a very well equipped electronics lab in your garage/cellar/attic this repair is way beyond doable (given you can even get a single - or two - chip/s from any wholesale outlet) or economically viable (if you can do it yourself it is "hours wasted", if you need to pay someone to do it it is "outside any reasonable amount").

This leaves you with the other option to replace the whole motherboard... which easily runs you down $100/150 (excluding P&P). For that "much" money you can actually pick up a new tablet having a faster CPU/GPU, more internal storage and a better resolution... spending it on a replacement motherboard would just be a waste of your hard earned money - unless you have a very specific need to cling on to this device (i.e. you implanted the tablet into the dashboard of your car - or any other "out of mind" mod). Apart from that... you would actually be able to make sure the replacement board has a eMMC that is not prone to bricking (like the M8G2FB that is in the device I played around with ... in this case it wasn't a problem of the chip, I'd rather say there's something very wrong with the CSD in Samsung's 4.2.2 firmware).

Buying a JTAG box is also too expensive. They run you down $200+ and then you need to educate yourself on the matter on how to get this piece of kit to good use, educate yourself on how to find JTAG ports on devices, and possibly also educate yourself on how to assemble connectors from scratch to connect to the pins or headers.

If you know a repair shop that has the knowledge to go into the device and equipment to JTAG it's butt... would be worth a try if it comes for cheap ... I wouldn't spend more than $50 max on a resurrection attempt.

In short: If you already got your money's worth out of the tablet then put it out of its misery and grab a new one... but better do your homework first to make sure you don't end up with just the next one having a "Shenzen market back-alley crap" eMMC built in. If you feel like you haven't squeezed your money's worth out of the tablet just yet ... well ... either try to find a repair shop that's not too overly pricey or try to snag a good deal on a replacement MoBo on eBay (given you feel like being able to tear the device apart to replace the board).