[syslinux] Buggy bios, boot of dos image hangs with syslinux, but not with isolinux

[Zipf Christian]

Hi 
We have a couple of FSC Computers here which seem to have a very strange
bios. I am trying to boot a MS-DOS disk to flash an Scsi Raid
controller.
Since the computer doesn't have a floppy anymore I tried syslinux from
an usb stick. The menu loads fine but I cannot boot disc images with
memdisk on this computer. It works fine on others, of course.
But now comes the weird part, if I use the same config with isolinux and
boot from cd it works on this computer.
I played around with raw, bigraw and safeint but nothing worked.

Here is the output:
Ramdisk at 0xdbef0000, length 0x002d0000
Disk is floppy 0, 2880K C/H/S = 80/2/36, EDD off
Using raw access to high memory
Total size needed = 2454 bytes, allocating 3K
Old dos memory at 0x9d800 (map says 0x9d800), loading at 0x9cc00
1588: 0xffff  15E801: 0x3c00 0x7cbe
INT13 08: Success, count = 0, BPT = 0000:0000
old: int13 = e320aaef int15 = e3200fab
new: int13 = 9cc0000a int15 = 9cc0037e
Loading boot sector... booting...
Starting MS-DOS

After that the computer completely freezes, and has to be powered down.

Does anybody know of a way around this?

Christian