"failed to load ldlinux.c32" when booting from USB is caused by writing the
isohybrid ISO at file level (drag-and-drop, Rufus "ISO" mode, UNetbootin), which
destroys the MBR/isolinux layout. The ISO build itself is correct — archiso's
bios.syslinux mode installs isolinux.bin + isohdpfx.bin + the c32 modules and
applies the isohybrid MBR, and the profile's bootmodes match upstream releng.
Add archiso/write-usb.sh: a safe block-level (dd) writer that lists removable
disks, refuses partitions and the system/root disk, requires an all-caps YES,
unmounts the target, then writes with conv=fsync. build.sh's completion output
now points at it and warns that file-level copies cause exactly this error.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Amir Alexander Abdelbaki