I googled long enough and I just found this that I didn’t know:
The above procedure is about 256Kb flash roms, but if it works successfully with 256Kb flash roms, it should be good 512Kb too I think.If you have a board that has only 1Mbit chip, but you need to reprogram 2Mbit chip - you may do it in two sets, first megabit last and second megabit first, as separate processes, when your first part is done, you will need to short PIN#30 (A17 for 2Mbit and PIN#NC in 1Mbit) to the ground and then flash second part.You will need to split file in two pieces, 1Mbit each (1Mbit=128kb), you may do it with any HEX editor, the only limitation for this process will be no support from flash chip for sector writing.
From Art of BIOS flashing
Anyway I tried as written above, I splitted my 512Kb bios file and flashed second 256Kb file first by Uniflash 1.40 without errors. So first set was ok.
When I instead flashed first 256Kb file last, I got and I’m always getting “Flash Data Verification Error” and all fails.
Please could anyone help me where I’m wrong?
Is the entire procedure correct?
Thanks