If - like me - you get stuck on boot after Manjaro updates to Linux Kernel 5.10, the solution is pretty simple:
- Boot into 5.9 (you can choose the option in the grub boot menu
- Reinstall the 5.10 kernel with:
sudo pacman -S linux510
- For good measure, reinstall the Nvidia driver (if you have an Nvidia card, that is) with:
sudo pacman -S linux510-nvidia
After that, the 5.10 kernel should boot.