Not sure if you reallay require a new BIOS. I think the interrupt call was done by your card but your monitor was not able to display it.
Just try some other values for the AL register:
http://www.ctyme.com/intr/rb-0069.htm
(Table 00010)
Values for video mode:
text/ text pixel pixel colors disply scrn system
grph resol box resolution pages addr
00h = T 40x25 8x8 320x200 16gray 8 B800 CGA,PCjr,Tandy
= T 40x25 8x14 320x350 16gray 8 B800 EGA
= T 40x25 8x16 320x400 16 8 B800 MCGA
= T 40x25 9x16 360x400 16 8 B800 VGA
01h = T 40x25 8x8 320x200 16 8 B800 CGA,PCjr,Tandy
= T 40x25 8x14 320x350 16 8 B800 EGA
= T 40x25 8x16 320x400 16 8 B800 MCGA
= T 40x25 9x16 360x400 16 8 B800 VGA
02h = T 80x25 8x8 640x200 16gray 4 B800 CGA,PCjr,Tandy
= T 80x25 8x14 640x350 16gray 8 B800 EGA
= T 80x25 8x16 640x400 16 8 B800 MCGA
= T 80x25 9x16 720x400 16 8 B800 VGA
03h = T 80x25 8x8 640x200 16 4 B800 CGA,PCjr,Tandy
= T 80x25 8x14 640x350 16/64 8 B800 EGA
= T 80x25 8x16 640x400 16 8 B800 MCGA
= T 80x25 9x16 720x400 16 8 B800 VGA
= T 80x43 8x8 640x350 16 4 B800 EGA,VGA [17]
= T 80x50 8x8 640x400 16 4 B800 VGA [17]
04h = G 40x25 8x8 320x200 4 . B800 CGA,PCjr,EGA,MCGA,VGA
05h = G 40x25 8x8 320x200 4gray . B800 CGA,PCjr,EGA
= G 40x25 8x8 320x200 4 . B800 MCGA,VGA
06h = G 80x25 8x8 640x200 2 . B800 CGA,PCjr,EGA,MCGA,VGA
= G 80x25 . . mono . B000 HERCULES.COM on HGC [14]
07h = T 80x25 9x14 720x350 mono var B000 MDA,Hercules,EGA
= T 80x25 9x16 720x400 mono . B000 VGA
08h = T 132x25 8x8 1056x200 16 . B800 ATI EGA/VGA Wonder [2]
= T 132x25 8x8 1056x200 mono . B000 ATI EGA/VGA Wonder [2]
= G 20x25 8x8 160x200 16 . . PCjr, Tandy 1000
= G 80x25 8x16 640x400 color . . Tandy 2000
= G 90x43 8x8 720x348 mono . B000 Hercules + MSHERC.COM
= G 90x45 8x8 720x360 mono . B000 Hercules + HERKULES [11]
= G 90x29 8x12 720x348 mono . . Hercules + HERCBIOS [15]
09h = G 40x25 8x8 320x200 16 . . PCjr, Tandy 1000
= G 80x25 8x16 640x400 mono . . Tandy 2000
= G 90x43 8x8 720x348 mono . . Hercules + HERCBIOS [15]
0Ah = G 80x25 8x8 640x200 4 . . PCjr, Tandy 1000
0Bh = reserved (EGA BIOS internal use)
= G 80x25 8x8 640x200 16 . . Tandy 1000 SL/TL [13]
0Ch = reserved (EGA BIOS internal use)
0Dh = G 40x25 8x8 320x200 16 8 A000 EGA,VGA
0Eh = G 80x25 8x8 640x200 16 4 A000 EGA,VGA
0Fh = G 80x25 8x14 640x350 mono 2 A000 EGA,VGA
10h = G 80x25 8x14 640x350 4 2 A000 64k EGA
= G . . 640x350 16 . A000 256k EGA,VGA
11h = G 80x30 8x16 640x480 mono . A000 VGA,MCGA,ATI EGA,ATI VIP
12h = G 80x30 8x16 640x480 16/256K . A000 VGA,ATI VIP
= G 80x30 8x16 640x480 16/64 . A000 ATI EGA Wonder
= G . . 640x480 16 . . UltraVision+256K EGA
13h = G 40x25 8x8 320x200 256/256K . A000 VGA,MCGA,ATI VIP
14h = T 132x25 Nx16 . 16 . B800 XGA, IBM Enhanced VGA [3]
[...]
What happens if you use
MOV AL, DD
? I think nothing will happen as mode DDh does not exist.
You can leave Debug with
q
and continue working with DOS if you have not figured out already.
I will see later if home if I also have some other Chips EGA card and will upload their BIOS.