I can guess on some 'basic' reasons:
Power Outage / System Crash - Enter incomplete and or corrupt values in memory addresses such that the card can't figure out what to do anymore.
Using a Different Card / Maker BIOS - Different order of memory addresses and or different sizes of memory addresses causing nonsense data and or overflowing and corrupting other memory addresses.
Setting some base value so high the card shuts down for protection and or constantly crashes.
Other Bits:
2) Have you ever 'bricked' a card by starting with that card's own default BIOS and modifying values from that (with non 'totally crazy' values)?
3) What seems to cause the biggest / most frequent issues with your past attempts?
4) What is preventing some cards from ever being re-flashed again?
Power Outage / System Crash - Enter incomplete and or corrupt values in memory addresses such that the card can't figure out what to do anymore.
Using a Different Card / Maker BIOS - Different order of memory addresses and or different sizes of memory addresses causing nonsense data and or overflowing and corrupting other memory addresses.
Setting some base value so high the card shuts down for protection and or constantly crashes.
- But beyond that. I don't know. Curious to hear your thoughts / info.
Other Bits:
2) Have you ever 'bricked' a card by starting with that card's own default BIOS and modifying values from that (with non 'totally crazy' values)?
3) What seems to cause the biggest / most frequent issues with your past attempts?
4) What is preventing some cards from ever being re-flashed again?