The deployed grub.cfg had its ${hiso_X} brace-form env var references
sed-mirrored to ${vtoy_X} to match the modsrc's Ventoy-original variable
names. But the modsrc's own C functions (vt_load_file_to_mem etc.) set
the env vars using the rebranded 'hiso_' name as written in the script,
so the brace-form mirror broke the round-trip: vt_load_file_to_mem set
hiso_font_mem_addr/size, but the loadfont immediately after read
${vtoy_font_mem_addr/size} (empty) and produced the 'error: invalid
font and no interface loaded' message at every boot.
The bare $hiso_X form still needs mirroring for the partition and chain
variables that modsrc's C code reads, so that sed remains. The brace
form is left untouched.
Verified in QEMU OVMF: with this fix, the font loads and the GRUB
rescue prompt no longer appears.
vasilito
e243d3494b