Quite simply, Desire as any other phone from HTC capable of prosyatsya from the SD card.
— It is sufficient to find the zip file with the update, rename it to update.zip and put it in the root of the SD card.
— Turn off phone, then hold Power+Volume Down phone will boot into bootloader HBOOT.
— From the menu choose recovery, you will see a triangle with an exclamation point.
— Hold down the Power button + Volume Up, a menu will appear.
— In recovery menu select Update from update.zip
All, the phone is officially flashed the official firmware.