I have googled a lot for this problem. I found this, but it didn't solve my problem. Other solutions suggest me to reinstall grub (run grub-install), which didn't work either.

Here is what I am doing: (my grub version is 2.02)

  1. I use grub2-mkrescue to make my X.iso
  2. I boot a VMWareWorkstation virtual machine, which has a 1.0GB SATA disk, from X.iso
  3. I install X.iso on disk, the details are:

3.1. erase /dev/sda in case there are old partitions on it: dd if=/dev/zero of=/dev/sda bs=1M count=1

3.2. Create 3 primary partitions on /dev/sda as dev/sda1,sda2,sda3 (the size is 100M, 30M and 70M), and toggle sda1 to be bootable

Disk /dev/sda: 1024 MB, 1073741824 bytes, 2097152 sectors
130 cylinders, 255 heads, 63 sectors/track
Units: sectors of 1 * 512 = 512 bytes

Device  Boot StartCHS    EndCHS        StartLBA     EndLBA    Sectors  Size Id Type
/dev/sda1 *  0,1,1       12,191,50           63     204862     204800  100M 83 Linux
/dev/sda2    12,191,51   16,147,2        204863     266302      61440 30.0M 83 Linux
/dev/sda3    16,147,3    25,127,37       266303     409662     143360 70.0M 83 Linux

3.3. Format the 3 partitions as ext2, and mount /dev/sda1

mkfs.ext2 /dev/sda1
mkfs.ext2 /dev/sda2
mkfs.ext2 /dev/sda3
mount /dev/sda1 $ROOTFS_PATH

3.4 copy files...

for i in bzImage initrd.img vmlinuz-*; do
    cp -rf /boot/$i $ROOTFS_PATH/boot
cp -f /boot/grub/device.map $ROOTFS_PATH/boot/grub/device.map
for i in init linuxrc; do
    cp -rf /$i $ROOTFS_PATH
for i in bin etc lib sbin share usr; do
    cp -a /$i $ROOTFS_PATH
for i in dev var proc sys tmp data log; do
    mkdir -p $ROOTFS_PATH/$i

3.5 Install grub and make grub config file

mount -a
mdev -s
grub-install $tdisk
grub-install --recheck $tdisk
grub-mkconfig -o /boot/grub/grub.cfg
  1. reboot

It says:

error: disk 'hd0,msdos1' not found
Entering rescue mode...
grub rescue>

And the most strange thing is that ls command shows nothing in grub-rescue cli ---- as someone says, it should show disk list.

error after reboot

  • Check your USB, for me it was the USB is not working properly because it's old and dusty May 5, 2021 at 21:08

1 Answer 1

cp -f /boot/grub/device.map $ROOTFS_PATH/boot/grub/device.map

So, you copied the GRUB device.map file from the GRUB rescue ISO image to your disk? It might be forcing grub-install to associate the GRUB device identifier hd0 with a disk device other than /dev/sda.

Before running grub-install, verify that the device.map file actually associates hd0 with the disk you're installing GRUB to (i.e. /dev/sda in your case).

Also, why are you doing all this? It looks like you're trying to make a grub2-mkrescue VM image that might be useable in rescuing some other VM that has lost its bootloader - is that what you're planning to do? If so, simply booting the problem VM using an ISO image of any Live CD/DVD Linux distribution would give you a more extensive set of tools and more comfortable environment for fixing your original problem, whether it's a missing bootloader or something else.

If you specifically need grub2-mkrescue, you already have your X.iso - why you are trying to convert it to a virtual-disk-based installation?

  • thanks for your reply. What I'm trying is to build a very small x86 Linux distro with only a few feature. Just like other Linux distro, Ubuntu,CentOS - Someone download a ubuntu-x.iso, boot from it and install it into the disk.That's what I want.
    – Hurry Zeng
    Mar 5, 2019 at 6:21
  • I want a disk-based installation, instead of a virtual-disk-based installation. However, I'm testing it on the virtual machine, before a real machine.
    – Hurry Zeng
    Mar 5, 2019 at 6:28
  • As this page says: If the device map file does not exist, then the GRUB utilities will assume a temporary device map on the fly. This is often good enough, particularly in the common case of single-disk systems. So I delete device.map from X.iso and donot copy it when installing, But the problem remained the same. Any other suggestions?
    – Hurry Zeng
    Mar 5, 2019 at 6:48

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