I applied updates earlier today and ran into an unrelated issue regarding the size of my boot partition. After taking what I thought were appropriate measures to delete old kernel versions, I could not reboot. I am brought to a blinking cursor (prior to the Luks decryption prompt). If I hit a key, I get the message

"Reboot and Select proper Boot device
or Insert Boot Media in selected Boot device and press a key"

Thinking I screwed something up, I decided to wipe the system entirely and reinstall Solus from scratch.

However, after installing Solus and updating all packages, I am once again presented with the same issue! This time I can go back to GRUB and select the (at this point pretty old) kernel that comes with 4.1 and get to the luks prompt.

No real customizations so far - I have a luks container set up exactly the same as before with the otherwise default prompts followed when installing Solus. Not dual-booting so it has control of the whole drive.

Edit: I'm currently running 5.4.12-144.current as that's what ships with 4.1. (It's not clear to me why that version is still available if I updated to 5.10.11, but at least I can still boot!)