Repairing Manjaro from Live ISO after update - Grub Problems

Hi,

Another noob struggling to boot Manjaro after the latest update.
I originally had the error that I was unable to use the latest Kernel (Didn’t screenshot)

I changed the Kernel to boot from and am now stuck at:
[Failed] Failed to start Load Kernal Modules
Etc
Etc
[Failed] Failed to mount boot/efi
[DEPEND] Depencdency failed for Local file Systems.
You are in emergency mode

I can not use the keyboard or access a terminal (Ctrl + Alt + F2)

I have created a live USB and have booted into that to try and repair the system.

I used Chroot - sudo manjaro-chroot -a
Tried to complete a system update:
sudo pacman -Syyu
:: Synchronizing package databases…
core 167.6 KiB 645 KiB/s 00:00 [##################] 100%
extra 1995.1 KiB 6.35 MiB/s 00:00 [##################] 100%
community 6.3 MiB 8.11 MiB/s 00:01 [##################] 100%
multilib 182.0 KiB 59.3 MiB/s 00:00 [##################] 100%
:: Starting full system upgrade…
there is nothing to do

and then tried an update of grub:
Sudo update-grub
Generating grub configuration file …
Found theme: /usr/share/grub/themes/manjaro/theme.txt
Found linux image: /boot/vmlinuz-5.8-x86_64
Found initrd image: /boot/amd-ucode.img /boot/initramfs-5.8-x86_64.img
Found initrd fallback image: /boot/initramfs-5.8-x86_64-fallback.img
Found linux image: /boot/vmlinuz-5.4-x86_64
Found initrd image: /boot/amd-ucode.img /boot/initramfs-5.4-x86_64.img
Found initrd fallback image: /boot/initramfs-5.4-x86_64-fallback.img
grub-probe: error: cannot find a GRUB drive for /dev/sda1. Check your devic
e.map.
grub-probe: error: cannot find a GRUB drive for /dev/sda1. Check your devic
e.map.
Adding boot menu entry for UEFI Firmware Settings …
Found memtest86+ image: /boot/memtest86+/memtest.bin
/usr/bin/grub-probe: warning: unknown device type nvme0n1.
done

I believe there lies the problem, but have no idea what it means or what I can do to fix it.

Any Help would be much appreciated!

Further information:
Single boot Manjaro only.
lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
loop0 7:0 0 24.4M 1 loop
loop1 7:1 0 539.3M 1 loop
loop2 7:2 0 1.6G 1 loop
loop3 7:3 0 656.3M 1 loop
sda 8:0 1 28.7G 0 disk
|-sda1 8:1 1 2.9G 0 part
-sda2 8:2 1 4M 0 part nvme0n1 259:0 0 931.5G 0 disk |-nvme0n1p1 259:1 0 300M 0 part /boot/efi -nvme0n1p2 259:2 0 931.2G 0 part /

mhwd-kernel -li
Currently running: 5.9.11-3-MANJARO (linux59)
The following kernels are installed in your system:

  • linux414
  • linux510
  • linux54
  • linux59

Fixed, but need help understanding what happened.

I followed some instructions to install the Linux 5.4.85-1 Kernel and then run my installation using 5.4.85-1.
I am now able to access my desktop environment again

Would anyone be able to explain why that worked and what to do for future updates?