My floppy is OK. I tested it in this mobo with vendor BIOS and also in other PC and working good. After apply incremental patch still Disk I/O error:
08.264: Booting from Floppy...
08.264: enter handle_13:
08.264:    a=00000201  b=00000000  c=00000001  d=00000000 ds=0000 es=07c0 ss=dd80
08.264:   si=00000000 di=00000000 bp=00000000 sp=0000fab8 cs=f000 ip=c9a2  f=0202
08.264: disk_op d=0x000f4500 lba=0 buf=0x00007c00 count=1 cmd=2
08.264: check_recal_drive 0
08.264: floppy_drive_recal 0
08.264: handle_0e
08.264: floppy_pio
08.264: floppy_pio
08.300: floppy_pio
08.682: handle_0e
08.682: floppy_pio
08.682: floppy_media_sense 0 ftype=4
08.682: floppy_drive_readid 0 rate=0 head=0
08.687: floppy_pio
08.689: handle_0e
08.689: floppy_media_sense finish 0 data_rate=0 fms=17 stype=4
08.690: floppy_pio
08.825: handle_0e
08.825: Booting from 0000:7c00
08.825: enter handle_13:
08.825:    a=00000201  b=00000700  c=00000002  d=00000100 ds=0000 es=0000 ss=dd80
08.825:   si=00007bd2 di=00000700 bp=00007c00 sp=0000fab8 cs=0000 ip=7d6e  f=0002
08.825: disk_op d=0x000f4500 lba=19 buf=0x00000700 count=1 cmd=2
08.825: floppy_pio
09.008: handle_0e
09.008: enter handle_13:
09.008:    a=00000201  b=00000700  c=00000010  d=00000100 ds=0000 es=0000 ss=dd80
09.008:   si=00007bd2 di=00000002 bp=00007c00 sp=0000fab8 cs=0000 ip=7d6e  f=0002
09.008: disk_op d=0x000f4500 lba=33 buf=0x00000700 count=1 cmd=2
09.014: floppy_pio
09.138: handle_0e
09.138: enter handle_13:
09.138:    a=00000201  b=00000900  c=00000011  d=00000100 ds=0000 es=0000 ss=dd80
09.138:   si=00007bd2 di=00000002 bp=00007c00 sp=0000fab8 cs=0000 ip=7d6e  f=0006
09.149: disk_op d=0x000f4500 lba=34 buf=0x00000900 count=1 cmd=2
09.149: floppy_pio
09.335: handle_0e
09.335: enter handle_13:
09.335:    a=00000201  b=00000b00  c=00000012  d=00000100 ds=0000 es=0000 ss=dd80
09.335:   si=00007bd2 di=00000002 bp=00007c00 sp=0000fab8 cs=0000 ip=7d6e  f=0006
09.335: disk_op d=0x000f4500 lba=35 buf=0x00000b00 count=1 cmd=2
09.341: floppy_pio
09.721: handle_0e
09.721: floppy error: 40 04 10 01 00 00 02
09.721: invalid basic_access:96:
09.721:    a=00000200  b=00000b00  c=00000012  d=00000100 ds=0000 es=0000 ss=dd80
09.722:   si=00007bd2 di=00000002 bp=00007c00 sp=0000fab8 cs=0000 ip=7d6e  f=0006
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I write how I build coreboot with SeaBIOS: