diary at Telent Netowrks

Switched out#

Wed, 26 Jun 2019 20:55:18 +0000

I have spent an inordinate amount of time lately to get a working NixWRT wireless extender running on my MT300A. The symptom is that whenever I reboot it, about 30-60 seconds later it will lock up every device on the switch it is plugged into for a minute - and as this presently includes my build system, which also serves as my NAS, the problem is a high-priority one.

I've had all kinds of hypotheses, many of which involved bridging loops somewhere on the LAN, but no amount of staring at network diagrams, poring over wireshark captures or or fiddling with STP seemed to have any effect. Until last night when I tried to do a TFTP boot forgetting that I'd unplugged it from the TFTP server, and that resulted in exactly the same problem without even starting the Linux kernel.

So, I guess we can eliminate NixWRT from our enquiries. Whether the problem is hardware, or is something to do with how U-Boot initializes the hardware - or both, even - I am in some sense cheered to learn that it was probably nothing I did. At this point I'm going to flash the latest extensino.nix build to it, put the cover back on, and go and plug it in somewhere I have wireless dead spots, so that I can actually start working on the new router that arrived last week. And maybe not reboot it too often, but actually I'm hoping that once the image can be booted from flash, U-boot won't need to initialize the network device at all and there will be no problem.

Well, I might just add in support for STP first, it seems like a sensible thing to have.