1) Back in the days of the 80486 (1995) where I lived in Coventry, England; there was an a con going on where computers were being sold as containing 2nd level cache memory, but in fact to save money, the cache memory was dummy. This was possible because the cache memory just sat on top of the memory bus and responded more quickly than main memory. The upgrade path was obvious to me: unsolder the bad cache memory directly from the board, and replace it with good cache memory DIP chips and sockets that I would buy for the purpose. Sure enough, the first unsoldered chip I smashed apart was a block of solid plastic – no silicon!
Well, unfortunately my soldering skills were not up to the task, and after all was said and done, it wouldn’t boot any more. Happy ending: I gave it to my dad who managed to fix it back up by replacing a bad power transistor that happened to be close to where I had been soldering.
2) A little later on I had an Athlon on MSI m/b machine I had decided to flash the BIOS to a newer version. Something went wrong and I was left with a bricked machine. Now, I actually had two machines at that time, and I’ve always been a fan of MSI motherboards so I happened to have two almost identical boxes. Inspiration struck and I booted up the working machine to DOS. Then, *while it was running*, I opened the case up and popped the BIOS chip out, replacing it with the bad one. This worked because the BIOS had been shadowed to main memory and didn’t care that it had just been gutted! I flashed the bad chip from DOS, popped it back out and returned it to the bad machine,…and crossed my fingers…
🙂 Worked like a charm.