Possible to install on a WNDR4300-TN?

Hi there

I bought an access point from my ISP, model number is WNDR4300-TN. Apparently the WNDR4300 has quite a bit of features but the -TN model is running on a VERY basic custom firmware.

I tried flashing openwrt via the web gui or tftp but the device does nothing after receiving the file.

Funnily enough, my switches actually report that the name of the access point is "OpenWRT". Not sure why that would be the case.

I found some very old log talking about changing some header but the archive link posted in the log is dead. (log)

Does anyone have any experience with these? Would love to use vlans and 802.1x on this thing.