Lenovo T420 (Maximized)

⚠️ Safety First

Before starting, please read our SPI Programmer Best Practices guide for essential safety information and programmer recommendations.

T420 Hardware Maintenance Manual

The thinkpad T420 has only one SPI flash chip that holds the BIOS, ME, etc. It is located under the palm rest. Similarly to the T430, to access this chip complete disassembly is required. It is a straightforward process and takes approximately 30 minutes. For this follow the T430/x230 guide.

Critical: Remove all batteries (including CMOS) AND disconnect the AC adapter before starting.

Here is the location of the chip. At some models the location of the dot where the red wire from programmer should go may be misleading. The dot you need is just black.

Note: See the SPI Programmer Best Practices for programmer recommendations (Tigard recommended; CH347F preferred budget option; CH341A rev1.6+ acceptable with a physical selector).

You should then follow through with configuring keys.