Lenovo X1
Flashing instructions
You have to remove the keyboard in order to access the flash IC (the chip inside the red circle on the picture above), as it is under the wider cable (already detached from MB in the picture) connecting the keyboard to the mainboard.
The flash IC can be a SOIC-8 one or a WSON-8 one, and may be covered with a piece of insulation tape.
For more details have a look at T420 / T520 / X220 / T420s / W520 common and the general flashing tutorial.
Steps to access the flash IC are described here X2xx series.