I've updated my firmware to workaround partial nvram loss problem. Everyone, who use my firmware, should upgrade to this latest version:
http://oleg.wl500g.info/gp/WL500gp-1.9.2.7-7f-pre7.trx
With this firmware, your unit would correctly detect RESET button state, regardless of nvram settings. I'm still investigating the reason for nvram loss - this is sort of hardware problem.
Updated to -pre7. Added a new workarounds for flash handling. Flash programing is now much faster, hangups should go away when commiting nvram changes. MirrorBit flash technology hacks added... nvram CRC checks are also added. Only kernel is updated.