Custom Ubuntu based iso won't boot if "USB Legacy Emulation" is disabled

I have a custom Ubuntu based iso which boots fine in BIOS mode on a Toshiba C55-A5310. It will also boot in UEFI mode if "USB Legacy Emulation" is enabled. With the machine is in UEFI mode and "USB Legacy Emulation" is disabled, the USB is not recognized. Here's the code I used to build the fat partition within the iso:

#! /bin/sh ############################ # Make UEFI partition # ############################ BOOT_IMG_DATA="$PWD" BOOT_IMG=efi.img mkdir -p $(dirname $BOOT_IMG) truncate -s 4M $BOOT_IMG mkfs.vfat $BOOT_IMG mkdir -p $BOOT_IMG_DATA/EFI/boot grub-mkimage \ -C xz \ -O x86_64-efi \ -p /boot/grub \ -o $BOOT_IMG_DATA/EFI/boot/bootx64.efi \ boot linux search normal configfile \ part_gpt btrfs fat iso9660 loopback \ test keystatus gfxmenu regexp probe \ efi_gop efi_uga all_video gfxterm font \ echo read ls cat png jpeg halt reboot mcopy -i $BOOT_IMG -s $BOOT_IMG_DATA/EFI :: 

Here's the code I used to build the iso:

############################ # Create the new ISO image # ############################ # The example names get mapped to their roles here orig_iso="$HOME"/foxclone/foxclone025-01.iso new_iso="$HOME"/foxclone/foxclone025-02.iso new_files="$PWD" mbr_template=/usr/lib/ISOLINUX/isohdpfx.bin # Extract MBR template file to disk dd if="$orig_iso" bs=1 count=432 of="$mbr_template" xorriso -as mkisofs "$new_files" \ -o "$HOME"/foxclone/foxclone025-02.iso \ -isohybrid-mbr /usr/lib/ISOLINUX/isohdpfx.bin \ -c isolinux/boot.cat \ -b isolinux/isolinux.bin \ -no-emul-boot -boot-load-size 4 -boot-info-table \ -eltorito-alt-boot \ -e boot/grub/efi.img \ -no-emul-boot \ -isohybrid-gpt-basdat \ -m grub.cfg "$new_files" 

Here's the result of fdisk -lu

larry@larry-Satellite-C55-A:~/foxclone$ fdisk -lu foxclone025-02.iso Disk foxclone025-02.iso: 549 MiB, 575668224 bytes, 1124352 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0x1e64812c Device Boot Start End Sectors Size Id Type foxclone025-02.iso1 * 0 1124351 1124352 549M 0 Empty foxclone025-02.iso2 288 5215 4928 2.4M ef EFI (FAT-12/16/32) 

Any help is appreciated

1 Answer

I would suggest using Rufus so you can either use Legacy or Other. One of them will work. Been there done that.