My router: AR300M running 3.105 (Nand).
So, I had some spare time and decided to try the latest snapshot build (3.201.0316.tar):
I loaded it through the GUI but instead of upgrading it actually downgraded to 2.26 Nor!
To cut a long story short, it took me several hours to get back to 3.105 Nand. I did this using Uboot (a pain to get the web page to open but finally did it*) and loaded 3.104 (3.105 failed).
A by product of this process was that I discovered the reset button does not work, other than to get me into Uboot.
*connected router to laptop using ethernet cable before powering up