I am trying to boot BAMT a Debian flavor via USB on a brand new Gigabyte GA-970A-UD3 motherboard. I tried various flash drive and various OS. I never had this problem with ASUS and MSI. The problem is from Gigabyte hardware.

I found that my BIOS is very strict about MBR compatibility. Now I can boot in DOS mode. The flash drive need to be formated as a Win98 Startup disk using HP USB disk storage format tool. Unetbootin menu is booting from USB but won't install BAMT.

If I use Windows or Linux diskimager the working MBR is deleted. I tried converting BAMT .img to .iso and it is not booting with Unetbootin.

Is it possible to boot BAMT(Debian Linux) from a Win98 DOS command prompt? Maybe there is a way to burn the image and keep the working MBR?

If the working MBR is deleted, the flash drive is not recognized at all by the BIOS.

This is the info I found that got me booting for the first time in DOS:

GB's BIOS will only boot USBs formatted to FAT-32, conforming to normal MBR 
bootloader. I've seen this before, and surmised that the 'stick-maker' was 
formatting in ReiserFile, or one of the EXT 'flavors', but no one ever followed 
up to confirm or deny... Also, if it's putting the bootloader into its own 
partition - won't work! 

In the BIOS, on the "Integrated Peripherals" page, the "USB Storage Function" 
item must be enabled (which should be the default) to allow USB booting... 

I've put a little work into a 'GB USB booting tutorial', and frankly, I'd just 
go ahead and finish it up for you, but I really don't want to reboot the several 
times it will take me to 'firm up' procedural details, and take the BIOS/boot 
pictures for the post - just noticed VAIL finally went 'public beta', so will be
downloading for likely twenty-six hours or so  There's likely enough there to 
test a 'raw DOS boot', just to see if your hardware (especially the USB stick 
itself) will do it...

Some post later:

Fixed. Here is a brief summary. Since my ubuntu live usb sticks (2gb kingston 
and 8gb sandisk sd/usb reader - fat32, created in ubuntu 10.04) would not boot 
this board even though they would boot my ga-ep45-ud3p, I decided to try 
bilbat's suggestion with the HP usb boot program. I created the win98 boot disk 
on the kingston 2gb stick without reformatting. It booted right up. Next, I used 
windows version of unetbootin to write the ubuntu live cd to the kingston disk. 
This fired right up and completed the install. Everything seems to be in good 
order now.

Unfortunately I can boot in DOS mode but can't boot BAMT.