6 ms·
Bypassing my school's BIOS password was easy. Open up "DEBUG" in a DOS prompt, and write a few-line assembly loop that writes increasing register numbers to po
by Peaker 14y ago
Bypassing my school's BIOS password was easy.
Open up "DEBUG" in a DOS prompt, and write a few-line assembly loop that writes increasing register numbers to port 70h (register select), and 0 to port 71h (value) -- to reset CMOS memory with all 0's.
Then you can just enter BIOS to set it all up from scratch.
- nshepperd 14y ago"Fortunately", back in the days when I was at school, the BIOS tended to have backdoor passwords that were easily googleable. That stopped working eventually, but then I happened to procure for myself a second-hand school computer which turned out to have the BIOS password still set when I bought it. Short work to then run a tool to read the password directly from CMOS. I've forgotten what it was, but for all I know they're still using the same password. Oh, the lengths I went to to run linux livecds...
- tripzilch 14y agoyou meant "altavistable", right? :)
- blhack 14y agoOr open the case and move a jumper.
- redthrowaway 14y agoOr just pop out the BIOS battery, short it with a paperclip for 30s, and pop it back in. Bingo, no more password.
- shenberg 14y agoFunny that you did it this way - I just wrote a single byte using 'o' directly from the prompt, which was enough to ruin the checksum and cause the bios to reset to defaults.
- k33l0r 14y agoI've personally seen a BIOS implementation (on an HP computer, I think) that would let you in if you typed in an incorrect password three times. That was pretty hilarious, maybe the programmers thought that nobody would be that tenacious?
- subsystem 14y agoCloned password prompt in basic and some social engineering for me :)
- voltagex_ 14y agoNow that's cool. Wonder if it still works.