MSDOS .EXE Debugger / Disassembler ?

[quantass]

My SCSI Host Adapter's BIOS has been wiped clean and the only way of getting it restored seems to be the supplied tool FLASH4.EXE from Adaptec. Unfortunately the tool refuses to reflash my adapter's bios because it is wiped clean. Go figure. It seems this is a good time to learn a bit about disassmbling/debugging a .EXE file. My goal is to patch the FLASH4.EXE file so that it bypasses the failsafe and reflashes my bios. I dont see the harm.

The file is 100KB, .EXE file under MSDOS using DJGPP Protected Mode.

I keep getting the error message "No BIOS Detected" from the FLASH4.EXE file so I figure if I had a tool which allowed me to search the file's disassmbled contents for where the phrase is used then worked backwards to find a condition statement (ie. JNZ) I could patch the area to skip to the correct location. What DOS based tool can help me do this? Under Windows I used a tool entitled Olly Debugger which was quite decent but unfortunately since the FLASH4.EXE file refuses to run under Windows Im forced to find a DOS based solution.

Thanks for any help.

[fishybawb]

It's been a long time since I touched a disassembler, but there's a version of Soft-Ice for DOS that I remember being pretty good. Take a look at http://www.exetools.com/ - there's all kinds of goodies there. Check the file with one of the analysers too, there's a chance it's compressed with PKLite or something similar - you'll need to uncompress it before disassembly. Good luck :)

[Terminator]

I'm assuming you know about low level programming and are very likely to be able to code in C. Try the following link to 'dcc decompiler" which will probably give you the C (remember not C++) code. You will get bounced to another site if you go for this but there are others there but C is alot easier to recode than assember...of course that depends on wether you like assembler... ;)

http://www.download.fm/index.php/Computers/Programming/Disassemblers/

I'd imagine you will probably have to do a wee bit of reverse engineering but not much with only 100K of exe file.

T

:t