This article applies to the GRiDCase 1520, 1530, 1535EXP, 1550SX, PalmPad 2350 series, PalmPad 2360 series, GRiD 1450, and maybe some others.

When I was faced with an unknown password after replacing the CMOS chip in my GRiDCase 1520 it was quite a project to sort out.  At the time I was unaware of the backdoor password built in to these machines.

When verifying a password the BIOS code will first hash the inputted password and then test it against the value stored in CMOS memory.  If it matches then the computer will boot.  If it doesn’t match then it will test it against a hash of characters extracted from the machine’s RTC date.  This would enable GRiD support to help customers who were locked out, at least that’s what I presume it’s for.

Analysis of BIOS dumps indicates that this technique was used in many GRiD computer models.  I wrote a simple utility which will generate the password.  A download is below.  Simply run it from the Windows console

Example: GridPassGen.exe 03/15/88