Thinkpads Forum

Just for information… [skip if not interested]

This may be useful to someone and save them some time. I wanted to use my 770 laptop to flash (write) my car’s PCM with an updated, high performance tuned program. The programs to read and to flash the PCM are in DOS and obviously have to access the com port. The procedure is to read the PCM a few times successfully and then flash it. (If errors happen during the flash/write, the PCM is junk and has to be sent away to have the flash memory replaced.)

I could not get the programs to work on my 770 running Win98 to by using a DOS window. The programs could not access the com port, even though HyperTerm and another program PCMComm had no problems. There were also several warnings from car forum members that it should be done in DOS, if possible. I tried restarting in DOS but again I could not access the com ports. I was going to have to boot into actual DOS from another media.

I have had several desktop systems have problems with their underused 3-1/2” floppy drives, so my first choice was to use the CD drive. I tried to create a boot CD that would allow access to the hard drive but did not have much success. I finally settled on using a floppy to get it booted and then shell to DOS (c:\windows\command\edb\command.com). I could then keep all the read/flash programs and .bin files in a separate directory. (We used this method successfully many years ago when I was a contractor at NASA and had to use an ESA-provided DOS software package to decomm and record serial data from our experiment in SpaceLab on the Shuttle.) I couldn’t get the serial ports to work on my 770 even with this setup.

I checked on IBM web site and found a DOS configuration program. I wrote this to a floppy and then added system files. After an initial setup, it worked well. I spent a lot of time coming to this solution, so I put it here in case it might help someone else.

RMC

If your system is running windows 9x there is a hidden file in C:/

This file is called MSDOS.SYS if memory serves (and it does I just checked)

Under [Options] add the second 3rd line below (BootMenu=1)


[Options]
BootMulti=1
BootMenu=1
BootGUI=1


You will, of course, have to unhide and un/system it (Use attrib command or windows explorer to do this) in order to edit it, you may edit with Notepad (NOT WORDPAD or WORD) I used a dos program myself

Once you have done this you will get a menu every time you boot, Normal, Safe mode DOS (command prompt) normal and safe mode and boot logged (not in that order) possibly something else, the default is normal boot (if you take no action) else a press of "enter" performs default or you can choose another boot method

This is how all my 9x computers are set up as a rule, Works great

SAFETY NOTE: MAKE BACKUP OF THE FILE BEFORE DOING ANY EDITING

You are fairly safe, but you never really know

And don't forget to re-set the attributes once you have edited it