UTC  Not necessarily  I believe SD  has tighter electrical specifications than SD x such as lower voltage tolerances and higher current tolerances so a SD x device may but would not necessarily qualify as an SD  device  It would need to be meet the electrical specs of SD  before it could be able to offically support SDHC and carry the SDHC logo  It is possible that some SD x devices will already meet this spec just because they were designed well from the start but they would need to be tested to ensure they meet the SD  electrical spec and also have a firmware upgrade      July