Anyone know how to 'destroy' the FAT12 boot sector so the system BIOS does not attempt to boot to the floppy (no 'invalid system disk' message) and will continue to the next boot device?

I know if I zero out the boot sector, it will achive the desired results, but I will also loose the FAT tables and all files on the disk. An ext2 formatted floppy will do just the same.

I need the floppy to be skipped during the boot process but still retain all files on the disk.

I have found utilities like BCTL500 that will rewrite the boot sector to skip the floppy and go to the hard drive but this is no good because I want it to move to the next boot device (CDROM).

Bart's jo.sys will not work either because I need this to work with FreeDOS.

Thanks a million for anyone that has this answer!!! I've been researching this for two weeks now.

In the bios you should be able to disable floppy boot seek!or change the boot sequence to C,A

Not good for my purpose, but thanks :)

Let me explain further....

I want to have a 'single boot' floppy disk. Basically I need to boot to it one time, run a couple tasks, and then I will rewrite the boot sector so that the next reboot the floppy disk will be skipped. But I also need the files on the floppy to still be accessable so zeroing out the boot sector will not work.

I had considered the option of just rewriting the disk with a non-bootable boot sector then changing the message to inform the user to change their boot order to CDROM, Floppy, HDD. But that wouldn't work either.

I have programmed in assembly language before, but not for x86, only 6502 (Apple II). That was back in '84, and it was more for education than pratical purpose (mainly because it's a pain). I guess if no one has an answer then I have no choice but to hit the books. ... now if I could just get an extra 24 hours per day to do it in :)



I'm probably out in left field here, but could you do some type of shell scripting here? Could you have some type of file on the floppy, say it's called noboot.txt. The first time the floppy boots, it does its needed tasks, and then creates noboot.txt. Then, the next time it boots, the script will check if there's a noboot.txt file there. If there's one there, it skips to the next boot sector.

I have no idea how to do this, though. My father in law does a lot with Multi-boot scenarios by copying various boot sectors. Maybe you could use a lilo boot disk. Just boot the floppy, do the tasks, and have a script that reruns lilo with a different lilo.conf, one which will only boot the CD-ROM device.

Just some ideas... hopefully they'll get some gears turning...

Yep, I've got the scripting part done for the most part. All I'm missing is the 'skip' boot sector.

Lilo was another thought I had too, and I think it's probably going to be the best one in the end. This way I can have it skip the boot disk unless they choose the option to boot to it.


Why dont you simply remove the Bios boot signiture at the end? AA55 i belive from the disk? That way it wont be bootable and the Fat structure will still be preserved.

If you use a Windows DMF format (1.67MB) floppy boot sector, the floppy will not boot and will be bypassed.


Copy the files to another disk, but do not make that disk bootable.

To do that:

Format the new disk.

Copy the files from the bootable disk to a temporary folder on the hard drive. Use "My Computer" to drag and drop the files.

Copy the files from the temporary folder to the blank formatted disk.

Now it should work. The drag and drop copying does not copy the active boot sector.