TIP: You do not need to touch anything in the firmware file, just download from tp link and use it straight in tftp (some tutorials will say to strip some part of the firmware, not needed for the v5)
Also, be sure to set the file name to
Upper case included, if the file name is wrong, you wont see any logs.
Do not use any of the openWRT methods of flashing using terminal(mtd -r, sysupgrade), their C7 wiki is mostly based for the V2 hardware(and the std dd wrt does not include sysupgrade), and will soft brick your V5 (which will need to be recovered using tftp, or worse, serial)
The first youtube video I found was using terminal to flash it and, of course, it did not work. It came up with a couldn't unlock something error. Afterwards, I had a router with only a glowing power light on. Found a second video that explained the TFTP method and this one worked. Bit stressful, but it's back.
I had flashed to DD-WRT with the intent of setting up OpenVPN, and no matter what I did, couldn't get it to work . . . it was like the script was not even running. Even had the VPN providers try for about an hour. I couldn't even get PPTP, so I figured I'd get things back to where I started. It was a fun