larry78723's questions

I have a custom iso based on Ubuntu 16.04 that is designed to run on a USB that boots in both Legacy (CSM) and EFI (with CSM support) modes just fine. When booting in EFI mode with CSM support, it's using the menu as defined in isolinux.cfg instead of the menu defined in grub.cfg, which I expected. It won't boot in EFI mode without CSM support at all.

I mounted my custom iso's efi partition and all it contains is bootx64.efi as a text file and no grubx64.efi. When I mount the efi partition from Ubuntu 16.04's iso, it has both bootx64.efi and grubx64.efi as programs. I'm pretty sure that I screwed-up the formatting of grub-mkimage and would appreciate some help on this. After mounting the iso, my method of modifying it is:

BOOT_IMG_DATA="$PWD"
BOOT_IMG=efi.img

mkdir -p $(dirname $BOOT_IMG)

truncate -s 4M $BOOT_IMG
mkfs.vfat $BOOT_IMG
mkdir -p $BOOT_IMG_DATA/EFI/BOOT
grub-mkimage \
    -C xz \
    -d "$HOME"/foxbuild2/src/livecd/image/boot/grub/x86_64-efi \
    -O x86_64-efi \
    -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 ::

# Create the new ISO image

# The example names get mapped to their roles here
#orig_iso=../foxclone.iso
new_iso=../foxclone025-4.15UEFI.iso
new_files="$PWD"
mbr_template=/usr/lib/ISOLINUX/isohdpfx.bin


xorriso -as mkisofs "$new_files" \
  -o "$new_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 isolinux/efi.img \
   -no-emul-boot \
   -isohybrid-gpt-basdat \
  -m grub.cfg

Thanks in advance, Larry

I've built a custom iso based on Ubuntu 16.04 that boots in both UEFI and CSM (was originally CSM only). I'd like to have grub use the menu in isolinux.cfg. Is there a way to manage this or do I have to build a separate menu in grub.cfg? My isolinux.cfg follows:

PROMPT 0
TIMEOUT 75
DEFAULT menu.c32
F1 help.txt

MENU RESOLUTION 1024 768
MENU TABMSG [F1] help  [Tab] options 
# Dimensions configured for 

MENU TITLE Foxclone

LABEL standard
MENU DEFAULT
MENU LABEL Start ^Foxclone
  KERNEL /casper/vmlinuz
  APPEND boot=casper initrd=/casper/initrd.lz vga=791 quiet splash --
TEXT HELP
   If boot fails, reboot and try
   selecting Safe Mode instead
ENDTEXT

LABEL safe
MENU LABEL ^Safe Mode
  KERNEL /casper/vmlinuz
  APPEND boot=casper initrd=/casper/initrd.lz xforcevesa nomodeset vga=ask toram --
TEXT HELP
   Prompts for a video mode and
   loads the USB image into RAM
ENDTEXT

LABEL check
MENU LABEL ^Check USB for defects
  KERNEL /casper/vmlinuz
  APPEND boot=casper integrity-check initrd=/casper/initrd.lz splash --
TEXT HELP
   Verify integrity of USB drive
ENDTEXT

LABEL memtest
MENU LABEL ^Memory test
  KERNEL /install/memtest
  APPEND -
TEXT HELP
   Check computer memory for errors
ENDTEXT

menu color screen   37;40      #80ffffff #00000000 std
menu color border   30;44      #40000000 #00000000 std
menu color title    1;36;44    #c00090f0 #00000000 std
menu color unsel    37;44      #90ffffff #00000000 std
menu color hotkey   1;37;44    #ffffffff #00000000 std
menu color sel      7;37;40    #e0000000 #20ff8000 all
menu color hotsel   1;7;37;40  #e0400000 #20ff8000 all
menu color disabled 1;30;44    #60cccccc #00000000 std
menu color scrollbar    30;44      #40000000 #00000000 std
menu color tabmsg   31;40      #90ffff00 #00000000 std
menu color cmdmark  1;36;40    #c000ffff #00000000 std
menu color cmdline  37;40      #c0ffffff #00000000 std
menu color pwdborder    30;47      #80ffffff #20ffffff std
menu color pwdheader    31;47      #80ff8080 #20ffffff std
menu color pwdentry 30;47      #80ffffff #20ffffff std
menu color timeout_msg  37;40      #80ffffff #00000000 std
menu color timeout  1;37;40    #c0ffffff #00000000 std
menu color help     37;40      #c0ffffff #00000000 std
menu color msg07    37;40      #90ffffff #00000000 std

Thanks in advance.

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

I am trying to add UEFI boot capability to a BIOS only Ubuntu 18.04 based custom iso. All the methods I've found so far require an efi.img file which isn't present in the iso. Can I use the file out of a full install Ubuntu 18.04? If yes, do I need to edit it? If not, how can I construct an efi.img file?

The custom iso is designed to run from a USB, not installed. It is also intended for distribution to new Linux users. Adding UEFI capabilities to the USB rather than the iso isn't the solution we're looking.

This is the script that I used to build the fat partition. It is run in the folder containing the extracted iso:

#! /bin/sh

BOOT_IMG_DATA="$PWD"
BOOT_IMG=efi.img

#Ensure needed folders exist

if [ ! -d "$BOOT_IMG_DATA"/efi/boot ]; then
  mkdir -p "$BOOT_IMG_DATA"/efi/boot
fi

if [ ! -d "$BOOT_IMG_DATA"/boot/grub ]; then
  mkdir -p "$BOOT_IMG_DATA"/boot/grub
fi

chmod -R +rw "$BOOT_IMG_DATA"/boot/grub
chmod -R +rw "$BOOT_IMG_DATA"/efi/boot

# Create the 64-bit EFI GRUB binary (bootx64.efi) and the El-Torito boot
# image (efiboot.img) that goes in the /isolinux directory for booting on
# UEFI systems.

# First, build bootx64.efi, which will be installed here in /EFI/BOOT:

grub-mkimage --format=x86_64-efi --output=bootx64.efi --config=grub.cfg --compression=xz --prefix=/EFI/BOOT part_gpt part_msdos fat ext2 hfs hfsplus iso9660 udf ufs1 ufs2 zfs chain linux boot appleldr ahci configfile normal regexp minicmd reboot halt search search_fs_file search_fs_uuid search_label gfxterm gfxmenu efi_gop efi_uga all_video loadbios gzio echo true probe loadenv bitmap_scale font cat help ls png jpeg tga test at_keyboard usb_keyboard

# Then, create a FAT formatted image that contains bootx64.efi in the
# /EFI/BOOT directory.  This is used to bootstrap GRUB from the ISO image.
dd if=/dev/zero of=efiboot.img bs=1K count=1440

# Format the image as FAT12:
mkdosfs -F 12 efiboot.img

# Create a temporary mount point:
MOUNTPOINT=$(mktemp -d)

# Mount the image there:
mount -o loop efiboot.img $MOUNTPOINT

# Copy the GRUB binary to /EFI/BOOT:
mkdir -p $MOUNTPOINT/EFI/BOOT
cp -a bootx64.efi -s $MOUNTPOINT/EFI/BOOT


# Unmount and clean up:
umount $MOUNTPOINT
rmdir $MOUNTPOINT

# Move the efiboot.img to isolinux:
mv efiboot.img isolinux
mv bootx64.efi efi/boot

echo
echo "Done building /EFI/BOOT/bootx64.efi and /isolinux/efiboot.img."

This is the script I use to build the iso:

#!/bin/bash

# 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=isohdpfx.bin


# Extract MBR template file to disk
dd if="$orig_iso" bs=1 count=432 of="$mbr_template"


# Create the new ISO image
xorriso -as mkisofs \
   -U  \
   -allow-lowercase  \
   -r -V 'foxclone025-02' \
   -o "$new_iso" \
   -J -J -joliet-long \
   -isohybrid-mbr "$mbr_template" \
   -c isolinux/boot.cat \
   -b isolinux/isolinux.bin \
    -no-emul-boot -boot-load-size 4 -boot-info-table \
   -eltorito-alt-boot \
   -e isolinux/efiboot.img \
    -no-emul-boot \
    -isohybrid-gpt-basdat \
   "$new_files"

Does anyone see a problem in the code? I really appreciate a different set of eyes looking at this as I think I've gotten "too close to the forest to see the trees".

EDIT: Contents of boot/grub and EFI/BOOT follows

larry@larry-Satellite-C55-A:~/foxclone/iso3$ ls -l boot/grub
total 2492
-rw------- 1 larry larry 2523136 Jul 31 01:33 efi.img
-rw------- 1 larry larry    5004 Mar 18  2019 font.pf2
-rw------- 1 larry larry     941 Aug  5 15:28 grub.cfg
-rw------- 1 larry larry     604 Aug  5 15:28 loopback.cfg
drwxr-xr-x 2 larry larry   12288 Jan 13 09:20 x86_64-efi

larry@larry-Satellite-C55-A:~/foxclone/iso3$ ls -l EFI/BOOT
total 2424
-rw------- 1 larry larry 1334816 Aug  5 15:28 BOOTx64.EFI
-rw------- 1 larry larry 1146744 Aug  5 15:28 grubx64.efi

Contents of grub.cfg

if loadfont /boot/grub/font.pf2 ; then
    set gfxmode=auto
    insmod efi_gop
    insmod efi_uga
    insmod gfxterm
    terminal_output gfxterm
fi

set menu_color_normal=white/black
set menu_color_highlight=black/light-gray

set timeout=5
menuentry "Foxclone" {
    set gfxpayload=keep
    linux   /casper/vmlinuz  boot=casper quiet splash ---
    initrd  /casper/initrd
}

#!/bin/bash

# The example names get mapped to their roles here
orig_iso="$HOME"/iso/foxclone.iso
new_iso="$HOME"/iso/foxclone025-02.iso
mbr_template="$HOME"/isohdpfx.bin
workdir="$HOME"/work
echo $HOME
echo $workdir is workdir
# Extract MBR template file to disk
dd if="$orig_iso" bs=1 count=432 of="$mbr_template"

# Create the new ISO image
xorriso -as mkisofs \
   -U  \
   -allow-lowercase  \
   -r -V 'foxclone025-02' \
   -o "$new_iso" \
   -J -J -joliet-long \
   -isohybrid-mbr "$mbr_template" \
   -b "$workdir"/isolinux/isolinux.bin \   <--------  fails here. The file does exist at that location.
   -c isolinux/boot.cat \
   -boot-load-size 4 -boot-info-table -no-emul-boot \
   -eltorito-alt-boot \
   -e boot/grub/efi.img \
   -no-emul-boot -isohybrid-gpt-basdat -isohybrid-apm-hfsplus 

Error in terminal I've been trying to fix this for 2 days, doing a crazy amount of research. Does anybody see anything that my old eyes have missed?

EDIT: Got it fixed by changing the line:

 xorriso -as mkisofs \

to

 xorriso -as mkisofs "$workdir" \       

and removing the reference to $workdir in the -b line