Yet another request. Hopefully I give just the right amount of info about what I've tried. BTW, I have a WZR-G300NHv1 (A0 D0).
I have followed your tftp instructions (basicallly, though I did add some "improvements"). I used linux, and used the following tftp params: rexmt 1, binary, verb, trace, timeout 1000. I was connected to port 4 (right next to the WAN port). Before doing all this, I set the computer's ethernet interface to 100T/full duplex/no autonegotiation, and I set a static IP address on my computer's eth0 port, and a static arp mapping of the router's IP to the router's MAC.
When I start the put command and plug in the router, the tftp attempts to retransmit 1000 times at 1 second intervals, but never sends a byte. During the tftp put attempts, I can verify that the interface settings are all still correct (computer interface is up and the IP address is set, arp map is correct, route shows route to router ip over eth0). The tftp put command times out.
I have repeated this using router IP addresses 192.168.11.1 and 192.168.1.1 (with matching computer IP addresses of 192.168.11.2 and 192.168.11.1 respectively) and router MAC addresses (the one on the router label, 02:aa:bb:cc:20, and 02:aa:bb:cc:1a) in all combinations sequentially with the same result. From the outside, it appears as though the router is booting the bootloader (the diag light comes on after 2 seconds, and stays solid for ~10 seconds, then flashes twice every three seconds forever). However, no tftp connection is ever made. Can you refer me to JTAG pinout data and JTAG client software, or serial debricking instructions? Or perhaps I've done something stupid?
Thanks, Rich