wolfordj@ihlpa.ATT.COM (452is-Wolford) (01/25/89)
I am trying to add/replace a drive type in my PHONENIX BIOS v3.10 00. I found where the drive table is and know the numbers that I want to put in the table, but after reading the rom, adding the numbers and "burning" a new set of rom, I get a rom check sum beep error code on boot and the machine hangs. Well that is no wonder since I did change the contents of the rom code and did not change the check sum, BUT: I can not seem to find where and how the check sum is computed, and/or checked. Any help would be greatful. BTW: This is a problem because the BIOS looks at the drive parameters instead of the drive description sector on the hard disk. My machine with AWARD BIOS does this just find. This same type of problem show's up when I want to read a 720K 5 1/4" (You know the 80TK DS/DD diskette). Seems the bios think that since it has 80 tracks that it must be a 1.2MB disk. Jeff Wolford att!iwsag!jww att!ihlpa!wolfordj harvard-+ | ucbvax--+---- att --+ iwsag!jww | decvax--+
royf@killer.DALLAS.TX.US (Roy Frederick) (02/02/89)
wolfordj@ihlpa.ATT.COM (452is-Wolford): > > I am trying to add/replace a drive type in my PHONENIX BIOS v3.10 00. > I used a public domain package called ROMU to update mine to support a Fujitsu M2243 Drive (11 heads, 754 (?) cylinders). The package consists of a small program and a doc file. The program copies your BIOS to a file, displays the drive table, updates it, and calculates the checksum. Not neccessarily in that order! I wrote a small program that compared a virgin set of ROM images (odd and even separated) to a modified set. Here are the changes noted: EVEN ----- 3309 00 <- 02 330b 00 <- ff 330f 00 <- 02 ODD ----- 3308 00 <- f2 3309 00 <- 0b 330b 00 <- ff 330c 00 <- 08 330e 00 <- f2 330f 00 <- 11 3fff 00 <- f6 (checksum) Then I took my chips out, copied them into memory of my programmer, typed in the changes, programmed new chips, installed the new ones. Voila! It worked! BTW, this was for drive type 35, I believe. At any rate it was an unused type. I also wrote a small C pgm to checksum a ROM in memory, mainly to determine the type of checksum used. If you need it - this stuff is available - I think I can locate it all - pack it - uuencode it - and mail it... but maybe this is enough info to do it without the little programs. Good luck! Roy Frederick (royf@killer.UUCP) Dallas County Data Services (214) 653-6340 504 Records Bldg. Dallas, TX 75202