Guide: https://droidwin.com/fix-fastboot-err...
In this video, we will show you various methods to fix the "Failed to Boot into Userspace Fastboot, One or more components might be unbootable" error when trying to flash a file in the FastbootD Mode.
00:53 Install Fastboot Drivers
02:39 Change Current Active Slot
04:47 Flash Fastboot ROM
06:55 Unbrick Tool