My Google Pixel 2 is stuck in a boot loop and after searching for ways to fix this online I found that applying a Rescue OTA to the device has solved a few people's issues.
Initially I downloaded the SDK Platform Tools from the android developer site and in my terminal, I cd'd into the platform-tools folder and used to command './fastboot devices' which showed my phones serial number, however my device wasn't listed when I used './adb devices' (typing the commands without the './' resulted in a "command not found" message). I then downloaded the SDK tools using homebrew instead and both 'fastboot devices' and 'adb devices' showed no devices.
I have no idea how to fix this. Google customer supports only suggestion was that I factory reset my phone but I haven't backed up my photos and was hoping to do that after I've exhausted all my other options.
fastboot devices
shows the device,adb devices
cannot, and vice versa – that's by design. ADB cannot show devices in fastboot/bootloader mode – and fastboot can do only that. You might wish to check out our corresponding tag wikis: adb and fastboot.