Practically-speaking, could I use a portable USB 2.0 HDD instead of a USB flash drive? My thinking is that 500GB sounds a lot nicer than 32 GB - 64 GB (cost-effective max), and I already have a 500GB drive laying around.
I tried with a 500GB USB 3.0 drive, but it didn't quite work (maybe because of the power requirements for USB 3.0?), and the drive doesn't have an A/C charger/power port. I have other smaller USB 2.0 drives I could try...
I'm using the TP-Link TL-MR3040 - and I tried it both powered and battery-only (same result: the SSID OpenWrt appeared but it wouldn't hand me an IP address).
~Jay