Sounds like you ereased a part of the flash that is supposed not to be ereased
You can probably restore it via JTAG or something, not sure how tho
I had installed DD-WRT v24 beta version for testing purposes. However it suddenly stopped working after couple of weeks. The funny story is that it fixed itself after quite few times disconnecting it from power source. This time the same symptoms but no remedy! all LAN LEDs are on. Restore and EZSETUP buttons do not function at all. No packet transferred from LAN and WAN ports. It does not read the flash boot either. I also tried to reset it through JP1 onboard. It didn't help. Taking out the mini PCI wireless adapter was not helpful too. Finally I thought it might be possible that someone knows how to rewrite the firmware through soldering some kind of JTAG or I2C like interfaces. Please help.