No RX power after KK2.1 V1.18S1 Firmware update.

Hi all i just want to warn people that they could render there boards completely useless by updating there firmware, I did everything as per the letter when flashing my firmware and found that the board would not power the Rx after updating, I then tried to revert to an earlier firmware update and it was the same, the Rx worked fine before updating the FC,

I have no idea why it works fine for some and not others as someone else had the same problem and was quietly ignored as no one offered any help and was completely blanked.

Anyway it looks like i now need to buy another FC board and i shall stay well away from these firmware updates in future.