Ping? The patch below fixes an off-by-one in /arch/amd64/stand/libsa/cmd_i386.c.
The affected code path is handling the machine boot command in the bootloader. Currently, trying to boot from MBR partition 'a', with a command such as machine boot hd0a, will in fact boot from whichever partition is flagged as active, rather than forcing a boot from partition 'a'. The bug was introduced in revision 1.20 of the original i386 architecture file over 20 years ago on 19980224. untrusted comment: verify with signify key for exoticsilicon.com RWRn5d3Yx35u0w51USyxAkjCzjLo99UNE67gXzvuaTGbD9cMlTKdDTOAOe7JA6LV/VLWqmomwo7D9m399vKnra2KyrUn/EYcUgo= --- arch/amd64/stand/libsa/cmd_i386.c.dist Fri May 10 18:20:43 2019 +++ arch/amd64/stand/libsa/cmd_i386.c Sun Aug 15 23:44:45 2021 @@ -107,7 +107,7 @@ dev += (cmd.argv[1][2] - '0'); part = (cmd.argv[1][3] - 'a'); - if (part > 0) + if (part >= 0) printf("[%x,%d]\n", dev, part); else printf("[%x]\n", dev); @@ -119,7 +119,7 @@ goto bad; /* Frob boot flag in buffer from HD */ - if ((dev & 0x80) && (part > 0)){ + if ((dev & 0x80) && (part >= 0)){ int i, j; for (i = 0, j = DOSPARTOFF; i < 4; i++, j += 16) --- arch/i386/stand/libsa/cmd_i386.c.dist Fri Jun 10 15:36:06 2016 +++ arch/i386/stand/libsa/cmd_i386.c Sun Aug 15 23:44:23 2021 @@ -119,7 +119,7 @@ dev += (cmd.argv[1][2] - '0'); part = (cmd.argv[1][3] - 'a'); - if (part > 0) + if (part >= 0) printf("[%x,%d]\n", dev, part); else printf("[%x]\n", dev); @@ -131,7 +131,7 @@ goto bad; /* Frob boot flag in buffer from HD */ - if ((dev & 0x80) && (part > 0)){ + if ((dev & 0x80) && (part >= 0)){ int i, j; for (i = 0, j = DOSPARTOFF; i < 4; i++, j += 16)