Device won't unlock for installation of /e/

[AnotherElk]

@MSI

If I restart the FF3 in fastboot mode, ADB no longer recognizes the device, and in the hardware manager on the PC I once again have the exclamation mark.

ADB doesn’t work in Fastboot Mode, so far so normal.
fastboot not working is odd.

@AnotherElk

Maybe there’s driver trouble. Here’s a generic driver and ADB/Fastboot repair …

• Disconnect the phone from the computer.
• In Control Panel - Programs and Features:
  Uninstall the Android SDK (if installed) and everything with “MTP” or “ADB” in its name.
• Reboot Windows.
• In Control Panel - Device Manager:
  Enable View - Show hidden devices, and then uninstall every possible ADB, MTP and smartphone device, hidden or not.
• Reboot Windows.
• Connect the phone again. (Windows should install the necessary drivers then automatically. They can be named after a different device, this doesn’t matter.)
• Download the current Android SDK Platform Tools
• Unzip the ZIP file to e.g. C:\platform-tools (you can unzip it to wherever you like).
• Add the path to where you unzipped the tools to the Windows “PATH” environment variable , so adb and fastboot could be run from everywhere without always having to prefix them with the path.

Then try fastboot devices again.