I do not know what is the nature of the problem you are having, but what I used a 8192-byte BIOS file that begins with the following hexdump:
0 00 38 4c c6 c6 c6 64 38 00 18 38 18 18 18 18 7e .8L...d8..8....~
10 00 7c c6 0e 3c 78 e0 fe 00 7e 0c 18 3c 06 c6 7c .|..<x...~..<..|
20 00 1c 3c 6c cc fe 0c 0c 00 fc c0 fc 06 06 c6 7c ..<l...........|
30 00 3c 60 c0 fc c6 c6 7c 00 fe c6 0c 18 30 30 30 .<`....|.....000
40 00 7c c6 c6 7c c6 c6 7c 00 7c c6 c6 7e 06 0c 78 .|..|..|.|..~..x
50 00 38 6c c6 c6 fe c6 c6 00 fc c6 c6 fc c6 c6 fc .8l.............
60 00 3c 66 c0 c0 c0 66 3c 00 f8 cc c6 c6 c6 cc f8 .<f...f<........
70 00 fe c0 c0 fc c0 c0 fe 00 fe c0 c0 fc c0 c0 c0 ................
80 00 3e 60 c0 de c6 66 7e 00 c6 c6 c6 fe c6 c6 c6 .>`...f~........
90 00 7e 18 18 18 18 18 7e 00 1e 06 06 06 c6 c6 7c .~.....~.......|
a0 00 c6 cc d8 f0 f8 dc ce 00 60 60 60 60 60 60 7e .........``````~
b0 00 c6 ee fe fe d6 c6 c6 00 c6 e6 f6 fe de ce c6 ................
c0 00 7c c6 c6 c6 c6 c6 7c 00 fc c6 c6 c6 fc c0 c0 .|.....|........
d0 00 7c c6 c6 c6 de cc 7a 00 fc c6 c6 ce f8 dc ce .|.....z........
e0 00 78 cc c0 7c 06 c6 7c 00 7e 18 18 18 18 18 18 .x..|..|.~......
f0 00 c6 c6 c6 c6 c6 c6 7c 00 c6 c6 c6 ee 7c 38 10 .......|.....|8.