How I flashed my Eeepc 901 in 2025? After a few attempts the following one was succesful:

I used a 4BG pendrive.

I downloaded rufus https://rufus.ie/en/ and formated pendrive with Freedos LiteUSB https://freedos.org/download/ - that created a bootable USB stick

AFUDOS Utility from https://www.asus.com/me-en/supportonly/ … _download/ (at the bottom of the list
- that's flashing tool old enough for my 901 BIOS

BIOS file from https://www.asus.com/me-en/supportonly/ … desk_bios/ that's most recent version.

I copied AFUDOS and BIOS to freeDOS pendrive, for simplicity renamed bios to 900.rom

Booted 901 from USB (TAB after powering then ESC for bootdevice selection then anykey to boot FreeDOS.

Optional - as a precaution/check I decided to dump current bios using command

afudos /oeeedump.rom

- it dumped bios as expected, a surprise lack of space after /o switch proves that file is rather ancient.

Finally I flashed BIOS using

afudos /i900.rom

YMMV. Good Luck