Ошибки, когда обновление

Я хотел вручную сделать:

sudo apt-get upgrade

и у меня есть ошибки в конце:

/usr/sbin/grub-mkconfig: 34: /etc/default/grub: Syntax error: EOF in backquote substitution
run-parts: /etc/kernel/postrm.d/zz-update-grub exited with return code 2
dpkg: error processing package linux-image-5.0.0-23-generic (--remove):
 installed linux-image-5.0.0-23-generic package post-removal script subprocess returned error exit status 1
Errors were encountered while processing:
 linux-image-5.0.0-23-generic
E: Sub-process /usr/bin/dpkg returned an error code (1)

Содержание /etc/default/grub:

# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
# For full documentation of the options in this file, see:
#   info -f grub -n 'Simple configuration'

GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=10
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=UUID="ef1f8271-5d94-4706-9904-61c9cd7da3ba"
GRUB_CMDLINE_LINUX=""

# Uncomment to enable BadRAM filtering, modify to suit your needs
# This works with Linux (no patch required) and with any kernel that obtains
# the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"

# Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console

# The resolution used on graphical terminal
# note that you can use only modes which your graphic card supports via VBE
# you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480

# Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true

# Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"

# Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"