Other SYS C:

no, but you can try the following. save the original boot sector with dd; newfs_msdos the disk in freebsd;copy ibmbio.com or io.sys first. copy ibmdos.com or msdos.sys next. copy the rest of the files. dd the original boot sector back. usually it works.
 
covacat said:
no, but you can try the following. save the original boot sector with dd; newfs_msdos the disk in freebsd;copy ibmbio.com or io.sys first. copy ibmdos.com or msdos.sys next. copy the rest of the files. dd the original boot sector back. usually it works.
Click to expand...
The original boot sector of what?
 
of the disk that you want to make bootable
the name of boot0 file is hardwired in the bootsector like ibmbio.com or msdos.sys for pcdos and msdos
the freebsd newfs_msdos wont have that code so you need an 'original' boot sector
 
What if I'm starting with a blank USB stick? Do I need to

sh: 
gpart destroy -F da0
gpart create -s mbr da0
gpart add -t f16 da0
newfs_msdosfs /dev/da0s1
mount -t msdosfs /dev/da0s1 /mnt
cp /dos/* /mnt
unmount /mnt
dd if=(dos.mbr) of=/dev/da0 bs=1 count=1

Something like that anyway...
 
dd if=(dos.mbr) of=/dev/da0 bs=1 count=1
don't do that / it will wipe your partititions
it's harder that way

you can try to dd a bootable floppy image directly to da0 / without any partition table
it may still work
 
the partition flag only tells bios to load the bootsector of the active partition and execute it
if the boot sector can't do its thing (missing boot files) tough luck
 
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it won't do it. to boot dos the msdos partition boot sector needs to load and run ibmbio.com or io.sys or or something
no such code is provided by freebsd
 
That would only write code to the boot sector. It could do it, if you actually have the code. You'd still miss io.sys, msdos.sys and command.com (for a bootable MS-DOS disk). Which is what the sys command writes to a disk to make it bootable.

IO.SYS - Wikipedia

en.wikipedia.org en.wikipedia.org
 
Emrion said:
Isn't it what needed?
Click to expand...
No, not for a bootable DOS (MS-DOS, DR-DOS, FreeDOS, etc) disk. It's not enough for FreeBSD either. The code in the master boot record can only be about 446 bytes, nowhere near enough. So the booting is done in stages, the code in the master boot record is only the first stage. FreeBSD's boot code is specifically written to look for FreeBSD boot code, nothing else.
 
SirDice said:
That would only write code to the boot sector. It could do it, if you actually have the code. You'd still miss io.sys, msdos.sys and command.com (for a bootable MS-DOS disk). Which is what the sys command writes to a disk to make it bootable.

IO.SYS - Wikipedia

en.wikipedia.org en.wikipedia.org
Click to expand...
I have the required files which I can easily add once the device is mounted.

I have just found that syslinux --install -f /dev/da0 gets my USB stick past the first hurdle and I get to a

boot:

prompt.
 
It's a terrible website, but I've gotten good boot disk images from them for all sorts of different operating systems.


I presume you need a DOS boot disk for a BIOS/UEFI firmware update? Maybe they have a UEFI shell update tool? Apparently some companies have firmware update tools that can be run from the UEFI shell.
 
SirDice said:
No, not for a bootable DOS (MS-DOS, DR-DOS, FreeDOS, etc) disk. It's not enough for FreeBSD either. The code in the master boot record can only be about 446 bytes, nowhere near enough. So the booting is done in stages, the code in the master boot record is only the first stage. FreeBSD's boot code is specifically written to look for FreeBSD boot code, nothing else.
Click to expand...
Nevertheless, it solves half of the problem if you want to keep your partition table as is.
 
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