I'm trying to install graphene on my pixel 4a. I've followed all the steps, but once I restart into the bootloader interface, my phone will not connect with any device. I tried using my laptop which runs linux. I tried using a windows PC. I even tried using another android phone. It will connect to other devices when it's in it's normal mode, but once I go to the bootloader, no such luck. If anyone has any ideas, please let me know, cause I'm about ready to give up.

Tried that earlier and nobody was able to help. I was hoping by making a post, maybe someone would stumble on it and have some insight.

I cannot help you but I feel like there was someone with a similar problem, only a few days ago. If I recall correctly that person was able to solve the problem but I cannot remember how. I think it may have been to kill the adb server? The problem was the device was still claimed ... or something else. But I don't remember how it was solved. Sorry I cannot help, but maybe you could try and use those buzzwords to find a solution. In case you find a solution make sure to report back on how you were able to solve it.

Yeah, that's part of the install instructions now. I'm about ready to give up on trying. I have one potential theory left to explore and that's that all the USB-C cables in my house are trash. I now seem not able to change the USB preferences to allow file transfer when it's booted up normally and I was able to connect and do that before, but now it will only charge.