After I checked Renice X3 (SF1222) mSATA SSD User Review, I decided to buy Renice X3 mSATA 120GB to update my X220i, but now MyDigitalDiscount is out of stock. I contacted Renice and brought this SSD from b2cit.com. I attached detailed update process, hope it can give you some instruction if you have not update x220i before.
RENICE 50mm mSATA
OK, let me take over the back side and disassemble the screws.
3、Turn back again and take out the keypad
Be carefully, Keyboard slip connect with blue connector, plug it out lightly!
Ok, Keyboard take it out.
Take over back again and start to disassemble screws in row.
Take out the back shelf.
OK, Now, we can start to replace the SSD.
Good. It rightly match with slot.