Chip works once, then nothing
OK, so if my Wii is uplugged for 10 or minutes, I load a backup game and it loads and works fine. Without powering down, if I eject the disc and load another backup game, I get the error. If I power down, restart, and load a backup game, I still get the error. If I unplug power for 10 to 15 minutes and load up a backup, it plays fine again. I upgraded the chip to firmware 1.2.
If you have fitted your chip with a WiiClip make sure there are no bent legs on the clip. If there is gently tease out to the centre a little with a TINY screw driver or similar to ensure a good contact between the legs on the clip and the legs on the main chip.
Hope this helps
firmware 1.2 sounds like wiikey2.
check if ur chip (/ clip) is genuine.
like bigtone stated in case of wiiclip usage:
check for bent pins and try refitting the clip.
check if the right points are soldered.
in case of direct soldering to the board:
check for long wires.
check for bad soldering.
make sure you write your images using imgburn at 4x speed with verbatim/memorex-r to make sure that's not the problem.