Yes i did.it became an .image file (APP_SW_X1i_GENERIC_UK_CDF1215-1832_KOV_R2AA010.image) then i renamed it and put it on the card...
Hmm, in that case ... the last possible reason I can think of is: the SD card is not formatted as FAT32.
Plug your X1 in your computer and look at the Storage Card properties, look at the "File system" and see what it says.