"Do you consistently see the fault in the same place?"
No, this is random place. I test BOOT-PROM3 disk and try boot PC more time. Every time is a different place e.g.:
lba=1051, lba=1086, lba=1015
but if try boot PC without any floppy inserted to FDD have this log:
Booting from Floppy... enter handle_13: a=00000201 b=00000000 c=00000001 d=00000000 ds=0000 es=07c0 ss=df80 si=00000000 di=00000000 bp=00000000 sp=0000f930 cs=f000 ip=cb97 f=0202 disk_op d=0x000f5520 lba=0 buf=0x00007c00 count=1 cmd=2 Floppy_drive_recal 0 Floppy_enable_controller handle_0e handle_0e WARNING - Timeout at floppy_wait_irq:206! Floppy_disable_controller Floppy_enable_controller handle_0e WARNING - Timeout at floppy_wait_irq:206! Floppy_disable_controller invalid basic_access:96: a=00000200 b=00000000 c=00000001 d=00000000 ds=0000 es=07c0 ss=df80 si=00000000 di=00000000 bp=00000000 sp=0000f930 cs=f000 ip=cb97 f=0202 handle_0e Boot failed: could not read the boot disk
enter handle_18: NULL Booting from DVD/CD...