This post in this case isn't directly related to '51 but just as well could be, and as result it can provide answer to quite important matter so please be gentle with "offtopic" moderation :)

Okay, I busted Flash in my cell phone. The phone comes with 64M Flash for MP3, but I kept abusing it as portable hard drive - and it seems the FAT area of the flash exceeded its write cycle limit - in short, I can't record anything and the media is corrupted.

The phone is after warranty but so instead of dumping it and simply getting a new one I'm up to some challenges like trying to fix it.

The most obvious solution would be to replace the flash chip with a new one of the same model. But since it's whole 64M, not quite cheap, my question is - would it be possible (and if so, how?) to get the abused piece of, say, 1-4M (I can test which part of memory is still writable and which is junk) address space overriden? This could be done by OR'ing say upper 4-6 address lines and using the output as switch using CE of the new/old chip. But would that be do'able in existing board? And won't the flash specifity like size of a page stand in a way?

It would be great if one could use a small NVRAM in place of the frequently written area. Not for use in my case I'm afraid but if you plan on using FLASH as a FAT drive, worth a thought - will prolong its life expectancy a lot (usually different areas of the drive are written much less than the FAT) but combining two such different memory devices as a Flash (cheap and big) and NVRAM (no write limit) in the same address space and making them blend transparently will be quite a challenge.