It works, the GL-MT300N and a HooToo Router have the same specs. I used the latest OpenWrt sources (modified a bit to show the correct model number) and edited the config files to have nano (WordStar like editor) as well as sftp and rsync plus usb and sdcard memory support.
After some work, the system shows as:
System
Hostname OpenWrt
Model RP-WD03
Firmware Version OpenWrt Designated Driver 50108 / LuCI Master (git-17.260.43176-678c15c)
Kernel Version 4.4.14
I will try to share the firmware file somewhere it can be found by a google search
the process of getting OpenWrt 15.05 Chaos Charmer(?) (clean firmware, no additions) is described in this forum by member loogatee under pid = 355628 # p355628
(Last edited by cycologist on 23 Sep 2017, 01:41)