Open the Settings app and go to Devices->Storage Devices
Tick "Use YAMT" and reboot the console
Using SD2Vita as the main user storage
Insert the SD2Vita adapter into the GameCard slot
Open the Settings app and go to Devices->Storage Devices
Set "ux0" to Default, "uma0" to SD2Vita and reboot the console
Launch VitaShell and copy all contents of "ux0:" to "uma0:"
Open the Settings app and go to Devices->Storage Devices
Set "ux0" to SD2Vita, "uma0" to Memory Card and reboot the console
VitaShell may throw an error while copying system files and folders such as "SceIoTrash", you must either skip or use a PC to copy them from the memory card onto the microSD card.