Aaak! I just had the same thing happen to me on an SL-5000D - Same procedure, but with a Sandisk 256mb CF. I prepared the zImage and initrd.bin on the card (24+8 zImage), pushed the C+D+reset combo. The 2 lights came on for a few minutes, and then went out. I turned it back to normal operation and... nothing. Since then I've removed all the cards, removed the battery, pushed full reset again, and still nothing.
Brick!
I re-did the files on the CF, and tried to reflash, but the C+D+reset doesn't do anything - no lights, no response whatsoever...
I removed the battery, I'm going to let it sit overnight and see what happens in the morning, but I'm a little worried for my poor collie...
Help!