[otellomoro]

I had just lost my wrt54gs V1.1 (see post below) and I decided to replace it with a wrt54gs V4 with V24RC3 on. I had to change configuration, so I restored factory defaults and I releoaded a previous V24-RC3 configuration.
Surprise, router bricked, power led blinking, lan led all green fixed, and all ethernet interfaces off (no signal).
It has been hard to unbrick. To reactivate ethernet interfaces and make the router pingable I had to ground pin 16 of the flash, (no way oin 15-16 short circuit) and then tftp the linksys firmware was not enough: at each reboot/save the router came back again with interfaces off and I had to restart from grounding pin16.
I was near to give up but I decided to try to tftp dd-wrtV24-standard.bin directly, without < 3M versions. That, and "mtd erase nvram" solved the problem.
Hope this information is useful to people having the same problem.