Can you successfuly boot at all..after 2,3...10 tries? If yes, try to install power kernel, I think it might help.
this might not relevant to the fault you are facing but did you try on any other battery?
Try pulling the battery for an hour, and then see if it'll boot (after putting the battery back in). This has consistently worked for me. Though this still doesn't address the main issue, which I'm not sure what it is. I'll need to reflash it at some point, it seems.
you could try using flasher booting from ubuntu with u-boot. Copy the flasher binary from maemo to an external location, boot ubuntu, copy flasher to /usr/bin, download images and try flashing (haven't tried it but it should work)