I've flashed factory images many times, including on this Nexus 5, and never had this happen before.
I'm using the USB cable that came with the Nexus 5.
I can boot back into fastboot, and everything works. I even flashed TWRP and can boot into TWRP. But in TWRP I can't mount anything, and if I try to do a system wipe, it fails.
Any thoughts? Has something somehow gone wrong while flashing the factory images? Help appreciated.
Edit: Booted into Stock Recovery and wiped cache and did a factory reset. Then rebooted from recovery and let it sit for awhile. It finally booted all the way up. Absolutely no idea what was going on there. Anybody else had a similar experience?