Error unknown command hwmatch [closed]

Solution 1:

Dealing strictly with the hwmatch problem look into /etc/grub.d/10_linux and you will find it listed something like this near the bottom (9th line down on this display):

# Use ELILO's generic "efifb" when it's known to be available.
# FIXME: We need an interface to select vesafb in case efifb can't be used.
if [ "x$GRUB_GFXPAYLOAD_LINUX" != x ] || [ "$gfxpayload_dynamic" = 0 ]; then
  echo "set linux_gfx_mode=$GRUB_GFXPAYLOAD_LINUX"
else
  cat << EOF
if [ "\${recordfail}" != 1 ]; then
  if [ -e \${prefix}/gfxblacklist.txt ]; then
    if hwmatch \${prefix}/gfxblacklist.txt 3; then
      if [ \${match} = 0 ]; then
        set linux_gfx_mode=keep
      else
        set linux_gfx_mode=text
      fi
    else
      set linux_gfx_mode=text
    fi
  else
    set linux_gfx_mode=keep
  fi
else
  set linux_gfx_mode=text
fi
EOF
fi

For whatever reason your grub installation is incomplete and missing hwmatch module. You should see it among many other files when you use ll /boot/grub/i386-pc:

-rw-r--r-- 1 root root  47292 Dec  5 07:13 hwmatch.mod
-rw-r--r-- 1 root root   2928 Dec  5 07:13 iorw.mod
-rw-r--r-- 1 root root   8656 Dec  5 07:13 iso9660.mod
-rw-r--r-- 1 root root   6168 Dec  5 07:13 jfs.mod
-rw-r--r-- 1 root root   6280 Dec  5 07:13 jpeg.mod
-rw-r--r-- 1 root root   5112 Dec  5 07:13 keylayouts.mod
-rw-r--r-- 1 root root   2044 Dec  5 07:13 keystatus.mod
-rw-r--r-- 1 root root   6608 Dec  5 07:13 ldm.mod
-rw-r--r-- 1 root root  29816 Dec  5 07:13 legacycfg.mod
-rw-r--r-- 1 root root  14536 Dec  5 07:13 legacy_password_test.mod
-rw-r--r-- 1 root root   8048 Dec  5 07:13 linux16.mod
-rw-r--r-- 1 root root  13184 Dec  5 07:13 linux.mod
-rw-r--r-- 1 root root    100 Dec  5 07:13 load.cfg
-rw-r--r-- 1 root root   5924 Dec  5 07:13 loadenv.mod
-rw-r--r-- 1 root root   3056 Dec  5 07:13 loopback.mod
-rw-r--r-- 1 root root   4872 Dec  5 07:13 lsacpi.mod
-rw-r--r-- 1 root root   2352 Dec  5 07:13 lsapm.mod
-rw-r--r-- 1 root root   1884 Dec  5 07:13 lsmmap.mod
-rw-r--r-- 1 root root   4136 Dec  5 07:13 ls.mod
-rw-r--r-- 1 root root   4928 Dec  5 07:13 lspci.mod
-rw-r--r-- 1 root root   6724 Dec  5 07:13 luks.mod
-rw-r--r-- 1 root root   6776 Dec  5 07:13 lvm.mod

As per this bug report (bugs.launchpad.net - Ubuntu Upgrade from Lucid to Precise results in broken grub configuration) the easiest way of getting all the grub modules is to reinstall it.

You should run sudo dpkg-reconfigure grub-pc and instruct it to install the boot loader somewhere, probably /dev/vda.

Above is a direct quote from the bug report. As a comment here points out and looking at your link, this should be used instead:

sudo dpkg-reconfigure grub-efi-amd64

However looking at this post (superuser.com - How to reinstall grub2 efi) you must first boot with a live USB/DVD and use:

sudo mount /dev/sda2 /mnt #sda2 is the root partition
sudo mount /dev/sda1 /mnt/boot/efi #sda1 is the efi partition
for i in /dev /dev/pts /proc /sys; do sudo mount -B $i /mnt$i; done
sudo cp /etc/resolv.conf /mnt/etc/ #makes the network available after chrooting
modprobe efivars # make sure this is loaded
sudo chroot /mnt

The first step is to confirm that the file hwmatch is really missing. If so the easiest method is to simply copy it from:

/usr/lib/grub/i386-pc/hwmatch.mod

into the directory:

/boot/efi/efi/grub

This directory name comes from (https://help.ubuntu.com/community/UEFIBooting) where they say that is "mostly" the directory name. Please confirm for your installation.

The more complicated methods of dpkg-reconfigure should be approached with extreme caution and only after appropriate backups.

Solution 2:

Did you try to use a different copy of your superblock (I think that 8193 and 32768 are examaples):

mke2fs -n /dev/XYZ 
...
Superblock-Sicherungskopien gespeichert in den Blöcken:
          32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, ...

Choose one copy of the superblock, e.g. the third one: In this case 163840 and do:

e2fsck -p -b 163840 /dev/XYZ

Solution 3:

For a Legacy boot, There's no reason you can't simply copy the spare file to the appropriate location as in sudo cp /usr/lib/grub/i386-pc/hwmatch.mod /boot/grub/i386-pc/hwmatch.mod

As my tests indicate that they are identical:

$ diff -s /usr/lib/grub/i386-pc/hwmatch.mod /boot/grub/i386-pc/hwmatch.mod 
Files /usr/lib/grub/i386-pc/hwmatch.mod and /boot/grub/i386-pc/hwmatch.mod are identical

For EFI mode:

I've checked a fresh install of 16.04 in EFI mode and hwmatch.mod doesn't exist so i would assume it can be safely ignored. If it annoys you I would suggest backing up your current grub.cfg, searching your grub.cfg for the insmod hwmatch line that's causing the issue and commenting it out to see if that alleviates the problem.