Relock the bootloader

Learningthings

So I got a pixel 4 and wanted to test all the different operating systems. I left the bootloader unlocked so I could switch between any I wanted. When I got to grapheneos I loved it and kept it. Now the issue is the bootloader is stuck to unlock. I tried to connect with the android tools via terminal window and run those but they can't find my phone. After looking for answers it seems the only option is to re flash it and lock it when I am done. Is that the case or can I re lock the bootloader and I am just missing something?

thrik

Learningthings For what it's worth, I always have a hard time getting my PC to recognize my phone in Fastboot whenever I infrequently need to. If you're in Windows, it could be that you need to either install the Google Drivers or just manually select them in Device Manager.

Wonderfall

It should be possible, but beware that locking or unlocking the bootloader wipes all the user data (for obvious security reasons). Boot your Pixel 4 in fastboot mode (Vol Down + Power), connect it to your PC with a known-good cable, and run the appropriate fastboot commands (fastboot devices will show you the list of connected devices).

Since this effectively wipes user data, you might be better off running the installation process again from the web installer. This time, follow all the instructions and you should be good.