I just tried it again with my 512K and it works OK here. Firmware 1.0L-F11. The only thing that's new in the latest firmware is LCD contrast adjustment, so it shouldn't have any effect on 128K/512K support unless I screwed up something. What kind of problem are you seeing when you try it? Does it work if you switch back to 1.0K-F11?

Might your 5V supply be out of adjustment? Or maybe something got damaged with the hardware when you had that glitch a few days ago?