The guide is for clones , but should work on genuine bricked boxes as well.
You can normally tell the clone from the mac address , as it should/could have the same numbering as the serial #
On the original boxes it looks like there is a 2nd copy of the bootloader on the 1Mb NOR flash , now this should not really have any impact on the flashing process , as the clone killer seems to wipe the 1Mb flash hence the reason the LED fails and it is bricked.
I think there may be a second firmware image of the NAND (not 100%) certain , would have to disect the dump i have to verify , but if there is as a failsafe , this could be a rev 22 clone killer image , I have seen in the bios settings they mention a Bank 1 and a Bank 2 , now i am not sure if this relates to the NOr or the NAND flash. If it relates to the NAND then there could be remanants of the Rev22 image on there (This is just speculation at the moment) , but it only seems to be yourself and sandy 22 who seem to be having the issue of it still failing.