Source: grub-installer Version: 1.194 Followup-For: Bug #1058638 I fetched the proposed patch and applied it to grub-installer inside the installer and can confirm it solved this issue.
syslog now shows "grub-installer: info: Installing grub on '/dev/vdb' and examining sector 0 of the disk image file shows the expected boot-strap code and a reboot correctly starts Debian: hexdump -n 512 -C disk2-debian-12.bin 00000000 eb 63 90 10 8e d0 bc 00 b0 b8 00 00 8e d8 8e c0 |.c..............| 00000010 fb be 00 7c bf 00 06 b9 00 02 f3 a4 ea 21 06 00 |...|.........!..| 00000020 00 be be 07 38 04 75 0b 83 c6 10 81 fe fe 07 75 |....8.u........u| 00000030 f3 eb 16 b4 02 b0 01 bb 00 7c b2 80 8a 74 01 8b |.........|...t..| 00000040 4c 02 cd 13 ea 00 7c 00 00 eb fe 00 00 00 00 00 |L.....|.........| 00000050 00 00 00 00 00 00 00 00 00 00 00 80 01 00 00 00 |................| 00000060 00 00 00 00 ff fa 90 90 f6 c2 80 74 05 f6 c2 70 |...........t...p| 00000070 74 02 b2 80 ea 79 7c 00 00 31 c0 8e d8 8e d0 bc |t....y|..1......| 00000080 00 20 fb a0 64 7c 3c ff 74 02 88 c2 52 be 80 7d |. ..d|<.t...R..}| 00000090 e8 17 01 be 05 7c b4 41 bb aa 55 cd 13 5a 52 72 |.....|.A..U..ZRr| 000000a0 3d 81 fb 55 aa 75 37 83 e1 01 74 32 31 c0 89 44 |=..U.u7...t21..D| 000000b0 04 40 88 44 ff 89 44 02 c7 04 10 00 66 8b 1e 5c |.@.D..D.....f..\| 000000c0 7c 66 89 5c 08 66 8b 1e 60 7c 66 89 5c 0c c7 44 ||f.\.f..`|f.\..D| 000000d0 06 00 70 b4 42 cd 13 72 05 bb 00 70 eb 76 b4 08 |..p.B..r...p.v..| 000000e0 cd 13 73 0d 5a 84 d2 0f 83 d8 00 be 8b 7d e9 82 |..s.Z........}..| 000000f0 00 66 0f b6 c6 88 64 ff 40 66 89 44 04 0f b6 d1 |.f....d.@f.D....| 00000100 c1 e2 02 88 e8 88 f4 40 89 44 08 0f b6 c2 c0 e8 |.......@.D......| 00000110 02 66 89 04 66 a1 60 7c 66 09 c0 75 4e 66 a1 5c |.f..f.`|f..uNf.\| 00000120 7c 66 31 d2 66 f7 34 88 d1 31 d2 66 f7 74 04 3b ||f1.f.4..1.f.t.;| 00000130 44 08 7d 37 fe c1 88 c5 30 c0 c1 e8 02 08 c1 88 |D.}7....0.......| 00000140 d0 5a 88 c6 bb 00 70 8e c3 31 db b8 01 02 cd 13 |.Z....p..1......| 00000150 72 1e 8c c3 60 1e b9 00 01 8e db 31 f6 bf 00 80 |r...`......1....| 00000160 8e c6 fc f3 a5 1f 61 ff 26 5a 7c be 86 7d eb 03 |......a.&Z|..}..| 00000170 be 95 7d e8 34 00 be 9a 7d e8 2e 00 cd 18 eb fe |..}.4...}.......| 00000180 47 52 55 42 20 00 47 65 6f 6d 00 48 61 72 64 20 |GRUB .Geom.Hard | 00000190 44 69 73 6b 00 52 65 61 64 00 20 45 72 72 6f 72 |Disk.Read. Error| 000001a0 0d 0a 00 bb 01 00 b4 0e cd 10 ac 3c 00 75 f4 c3 |...........<.u..| 000001b0 00 00 00 00 00 00 00 00 13 43 3c 32 00 00 80 04 |.........C<2....| 000001c0 01 04 83 fe c2 ff 00 08 00 00 00 90 3b 00 00 00 |............;...| 000001d0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................| * 000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.| 00000200
