kotel wrote on 2025-02-18, 12:39:

Now I don't know how am I supposed to dump this BIOS. Reading without those two pins results with it reading blank.

AT29C020 is a Flash, not EEPROM. No difference for reading but do make sure you've selected correct device as some EEPROMs have different pinouts. And speaking of, what package are we talking about, DIP32? In that case pins 25 and 27 are A11 and A8. While missing them will prevent you from dumping the contents you should get something out, it's just two address lines, the rest should still work. If all you get is zeros then either the programmer config is wrong or the chip is properly dead. Well, could be zero'ed and damaged too I suppose, but that is still no dump possible situation.

Flash degrades with heating. Try cooling it first, if that doesn't work you can try heating. These are usually done to try and stabilize any weak bits, not to make the whole chip work again, but at this point you can try. Do make sure you've also scrubbed the VCC and GND pins, because poor power delivery can also cause weird issues.