GRUB into BusyBox

Before completely reinstalling I’d like to try to get some help here; I’ve updated Ubuntu yesterday. After the next restart my system booted into the GRUB command line (as described in many other threads, e.g. https://unix.stackexchange.com/questions/474510/unwanted-grub-command-prompt-while-booting). After following pretty much every guide I was able to execute the boot command after linux /boot/<path-to-image> initrd /<path-to-image>…

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