Comment # 2 on bug 1230345 from Ruediger Oertel

well, this worked with the same IBS/OBS worker images all the time.

reducing to 1 entry, running with "-V":

s390zl21:/ # zipl -V -c /boot2/zipl.conf.min 
Looking for components in '/lib/s390-tools'
Using config file '/boot2/zipl.conf.min' (from command line)
Secure boot support: yes
Run /lib/s390-tools/zipl_helper.device-mapper 254:1
Target device information
  Device..........................: fe:01 *)
  Partition.......................: fe:01
  Device name.....................: dm-1
  Device driver name..............: device-mapper
  Type............................: disk partition
  Disk layout.....................: SCSI disk layout *)
  Geometry - start................: 0 *)
  File system block size..........: 4096
  Physical block size.............: 512 *)
  Device size in physical blocks..: 8388608
  *) Data provided by script.
Building bootmap in '/boot2/zipl'
Building menu 'menu'
Adding #1: IPL section 'KIWI_SLES15_20240909' (default)
  initial ramdisk...: /boot2/initrd-kiwi-20240909.xz
  kernel image......: /boot2/kernel-kiwi-20240909
Run /lib/s390-tools/zipl_helper.device-mapper 254:1
  kernel parmline...: 'hvc_iucv=8 TERM=dumb switch_amode console=sclp_line0
console=ttyS0 bond_mode=1 kiwiservertype=http
kiwiimage=workers/test-s390x-kvm/image-current.xz kiwidebug=1
kiwikernelmodule=scsi_dh_alua ELOG_EXCEPTION=/dev/sclp_line0
ELOG_BOOTSHELL=/dev/ttysclp0
cio_ignore=all,!ipldev,!condev,!f900,!fa00,!fc00,!f100-f123,!f200-f223
crashkernel=64M-:32M net.ifnames=0 sysctl.vm.allocate_pgste=1
transparent_hugepage=never'
Run /lib/s390-tools/zipl_helper.device-mapper 254:1
  component address:
    heap area.......: 0x00002000-0x00005fff
    stack area......: 0x0000f000-0x0000ffff
    internal loader.: 0x0000a000-0x0000dfff
    parameters......: 0x00009000-0x000091ff
    kernel image....: 0x00010000-0x00a06fff
    parmline........: 0x00a08000-0x00a081ff
    initial ramdisk.: 0x00a20000-0x0714fdff
    environment blk.: 0x00a18000-0x00a18fff
zIPL environment block content:
Preparing boot device for LD-IPL: dm-1.
Error: Unsupported SCSI disk layout


end of strace:

3460311 write(3, "zSeries bootmap file\ncreated by "..., 512) = 512
3460311 lseek(3, 49664, SEEK_SET)       = 49664
3460311 write(1, "  component address:\n", 21) = 21
3460311 write(1, "    heap area.......: 0x00002000"..., 44) = 44
3460311 write(1, "    stack area......: 0x0000f000"..., 44) = 44
3460311 write(1, "    internal loader.: 0x0000a000"..., 44) = 44
3460311 write(1, "    parameters......: 0x00009000"..., 44) = 44
3460311 write(1, "    kernel image....: 0x00010000"..., 44) = 44
3460311 write(1, "    parmline........: 0x00a08000"..., 44) = 44
3460311 write(1, "    initial ramdisk.: 0x00a20000"..., 44) = 44
3460311 write(1, "    environment blk.: 0x00a18000"..., 44) = 44
3460311 lseek(3, 0, SEEK_CUR)           = 49664
3460311 write(3,
"zIPL\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 512) = 512
3460311 fstatfs64(3, 88, {f_type=EXT2_SUPER_MAGIC, f_bsize=4096,
f_blocks=1030072, f_bfree=943135, f_bavail=890707, f_files=262144,
f_ffree=262115, f_fsid={val=[0xb175a6e9, 0x95ddf447]}, f_namelen=255,
f_frsize=4096, f_flags=ST_VALID|ST_RELATIME}) = 0
3460311 ioctl(3, FS_IOC_FIEMAP, {fm_start=49664, fm_length=4096,
fm_flags=FIEMAP_FLAG_SYNC, fm_extent_count=1} => {fm_flags=FIEMAP_FLAG_SYNC,
fm_mapped_extents=1, ...}) = 0
3460311 write(1, "zIPL environment block content:\n", 32) = 32
3460311 lseek(3, 0, SEEK_CUR)           = 50176
3460311 write(3,
"zIPL\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0040\t\2\0\0\0\0\0\0\0"..., 512) = 512
3460311 fstatfs64(3, 88, {f_type=EXT2_SUPER_MAGIC, f_bsize=4096,
f_blocks=1030072, f_bfree=943135, f_bavail=890707, f_files=262144,
f_ffree=262115, f_fsid={val=[0xb175a6e9, 0x95ddf447]}, f_namelen=255,
f_frsize=4096, f_flags=ST_VALID|ST_RELATIME}) = 0
3460311 ioctl(3, FS_IOC_FIEMAP, {fm_start=50176, fm_length=4096,
fm_flags=FIEMAP_FLAG_SYNC, fm_extent_count=1} => {fm_flags=FIEMAP_FLAG_SYNC,
fm_mapped_extents=1, ...}) = 0
3460311 write(1, "Preparing boot device for LD-IPL"..., 40) = 40
3460311 openat(AT_FDCWD, "/dev/zipl0000", O_RDWR) = 4
3460311 ioctl(4, BLKFLSBUF)             = 0
3460311 lseek(4, 0, SEEK_SET)           = 0
3460311 read(4,
"zIPL\0\0\0\1\0\0\0\0\0\0\0\0\0\0\0\0\0\0\200\10\2\0\0\0\0\0\0\0"..., 512) =
512
3460311 fsync(4)                        = 0
3460311 close(4)                        = 0
3460311 close(3)                        = 0
3460311 unlink("/boot2/zipl/bootmap_temp.XoknWX") = 0
3460311 unlink("/dev/zipl0000")         = 0
3460311 write(2, "Error: Unsupported SCSI disk lay"..., 36) = 36
3460311 exit_group(1)                   = ?
3460311 +++ exited with 1 +++