Updated April 3 2021##

This is list of Windows 10 (64bit) T420 drivers that might be useful to someone else and to make sure I have the latest version of "all the things," and whether I missed anything. All tested on my personal T420-4180CM6 (except SmartCard and Fingerprint Reader, which I don't have). It should make most of the FN keys work, among other things.

Not all drivers are absolutely necessary, a lot of things work okay with the genericAF Windows drivers, I just made this list to be thorough. Some of the Windows 7 drivers are actually newer than the generic Windows ones...

IMPORTANT NOTES NOV 2019

I'm currently working on updating this list, Lenovo in their infinite wisdom keeps mucking with Vantage, which wreaks havoc with the house of cards that is the combination of Lenovo PM, Lenovo Power Management, and the Lenovo Interface Foundation.

A lot of this just installing the new driver doesn't work, you have to manually update via Device Manager, a number of system devices will find updates from M$ if done manually -- I added a list of the devices this works for below.

Mini-rant about "Driver Updater" Software

I've tried a lot of them, they'll try to get you to pay money to install drivers from dubious sources that won't work for your system anyways. For example, the 12.x.x.x version of Bluetooth drivers are for BT4.0 and make 3.0 devices not work.

If they told you the truth about your system being up to date and didn't find anything, they wouldn't be able to scam you into buying a copy.

Windows 10 1903

I did have to "force" the update using the Windows Update Tool as it was giving me the "Your Device Isn't Ready." So far, everything seems to work just fine with a few exceptions:

1. The Camera App didn't work even with the default drivers. I forced the Realtek drivers AGAIN and it works. (see below for more information)

2) A "MAP SMS/MMS" in Device Manager with a question mark when a cellphone is Bluetooth linked. Under "Devices and Printers" in Control Panel find your mobile device -> right-click -> properties -> services tab. Uncheck MAP SMS/MMS.

Windows 10 1909

No notable issues thus far. At least not driver-related ones.

Windows 10 20H2 UPDATE IMPORTANT

DO NOT install any Conexant drivers, just use the windows default.

&nbspl

I had to do a clean install of windows 1909 with no drivers installed and let it update from that. The various epic things I tried to do to get rid of the conexant drivers didn't work, and 20H2 went into a bluescreen loop.

Security Update

T420 Bios 1.52

    https://pcsupport.lenovo.com/us/en/products/LAPTOPS-AND-NETBOOKS/THINKPAD-T-SERIES-LAPTOPS/THINKPAD-T420/downloads/DS018784

DVD drive DLL fix!

After installing the PM Drivers and Power Management Drivers (I wish these were named more distinctively, but Lenovo) copy PWMTR32V.dll from

    FROM:

        C:\Windows\SysWOW64\Lenovo\PowerMgr\

    TO:

        C:\Windows\System32\Lenovo\PowerMgr\

M$ default AHCI drivers are buggy

Intel RST VERSION 12.9.4.1000 (latest I could find for Series 6 Chipset)

    https://www.station-drivers.com/index.php?option=com_remository&Itemid=353&func=fileinfo&id=687&lang=en

Full FN Key Functionality, Touchpad, TrackPoint, Fingerprint Reader

(04/21) Lenovo System Interface Foundation AFAIK should be installed by Vantage

Hotkeys didn't work properly for me until I installed both versions in order

Hotkey Integration Features PART 1 (W7) 8.86.25

    https://support.lenovo.com/us/en/downloads/ds101334

Hotkey Integration Features PART 2 (w10) 9.0.1.3     https://support.lenovo.com/sg/en/downloads/ds031814

(11/19)ThinkPad Power Management Driver (PM Device) 1.67.17.28 needed by Vantage

    https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkpad-x-series-laptops/thinkpad-x390/downloads/DS539633

(04/21) Lenovo Power Manager 10.0.134.0 needed by Vantage

    https://support.lenovo.com/hk/en/downloads/ds541411-lenovo-settings-power-manager-for-windows-10-version-1703-or-later-thinkpad

Lenovo Vantage Set battery threshold, add toolbar, some FN keys open this so they won't work w/out it

    https://www.microsoft.com/en-us/p/lenovo-vantage/9wzdncrfj4mv?activetab=pivot:overviewtab

Synaptics UltraNav (Touchpad + Trackpoint) 19.0.17.141

    https://support.lenovo.com/us/en/downloads/ds103454

Synaptics Fingerprint Reader (WBF)(0017) 4.5.513.0 Untested, I don't this on my model

    https://www.catalog.update.microsoft.com/Search.aspx?q=synaptics%20FP%20sensors%20(PID%3D0017)%20

Quirky

It took some wrestling with Windows to make it keep these and not auto-install ones that didn't work -- namely trying to install Ricoh drivers when it's not a Ricoh device. If your camera isn't working after installation, check to make sure the driver version matches the correct manufacturer (ie, not Ricoh) in Device Manager.

It didn't seem to matter which device I picked when manually installing the driver, as long as I picked one of the Realtek ones.

Under Device Manager -> Details -> Hardware ID's VID_04F2 is Chicony, which uses a Realtek Chip.

Integrated Camera Driver 10.0.18362.20112

    https://support.lenovo.com/us/en/downloads/ds502998

Brief instructions for "Forcing" the driver:

    Update Driver

    Browse my computer for driver software

    Let me pick from a list of available drivers

    Have Disk

    Copy manufacturer's files from C:\DRIVERS\CAMERA\N29CA04W (default location)

    Realtek -> Integrated Camera (may have to experiment with which Realtek to pick)

    Update driver warning [Yes]

Additional note - the W10 Camera App is . . . quirky (to put it nicely) about detecting the camera. The camera may still work in other apps. I personally found an OEM version of Cyberlink's YouCam 6 that (A) works more consistently and (B) offers more functionality than the W10 App.

For some users, the Rico SD card thing causes 100% cpu usage, either disable/enable in Device Manager as needed or just get an external card reader.

Ricoh Media Card Reader Driver 2.25.18.01     https://pcsupport.lenovo.com/us/en/downloads/DS038445

Other

Lenovo Active Protection System 1.82.0.20

    https://support.lenovo.com/us/en/downloads/ds014892

ThinkPad Monitor INF File 6.11.1.0 (Manual Install)

    https://support.lenovo.com/ca/en/downloads/ds502266

    Once the monitor is properly identified, check for driver updates in W10

Better ICC Profile

    https://www.dropbox.com/s/jsllt9686nivaod/T420_ICC.zip?dl=0

Intel Chipset Support 10.1.1.38

    https://ftp.station-drivers.com/index.php?option=com_remository&Itemid=352&func=fileinfo&id=2476&lang=en

Intel 6205 (wifi) 15.18.0.1 (Manually switch from Microsoft to Intel)

    https://www.catalog.update.microsoft.com/Search.aspx?q=6205

Intel 82579ML 12.15.31.4

    https://www.catalog.update.microsoft.com/Search.aspx?q=82579LM

Intel 3000HD Graphics 9.17.10.4459

    https://www.catalog.update.microsoft.com/Search.aspx?q=HD%203000

    Windows 10 default should be the newest.

Broadcom BCM2045B (Bluetooth Dongle, Install manually) 6.5.1.6820

    https://www.catalog.update.microsoft.com/Search.aspx?q=bluetooth%20dongle

    *DON'T use the 12.x.x.x drivers, those seem to be for BT4.0 and made mine not work.

Conexant 20672 (Sound)

DO NOT USE CONEXANT DRIVERS -- use the default HD Audio Device drivers. They cause serious issues with Windows 20H2

Conexant 11270 (Modem) 7.80.8.50

    https://support.lenovo.com/us/en/downloads/ds013944

(11/19) nVidia 4200m (perpetually updates, check site), can use Geforce for GT520M if you like.

    https://www.nvidia.com/Download/index.aspx?lang=en-us

Smart Card Reader 4.1.0.1 Untested, it's not on my model

    https://support.lenovo.com/us/en/downloads/ds014067

Thermal Controls

In my experience the T420 runs hot, TPFC is needed to make the fan run full speed (~6000rpm)

I use Throttlestop set up to still allow throttling for safety, but only down to 2GHz instead of 800MHz

ThinkPadFanControl USE v063 for T420

    https://thinkwiki.de/TPFanControl

ThrottleStop 8.70.6

    https://www.techpowerup.com/download/techpowerup-throttlestop/

My TPFanControl.ini temperature section (T420 w/ 4200M)

    https://jpst.it/1H_dc

My ThrottleStop settings *Updated, using 'set multiplier' instead of 'clock modulation' kept it from downclocking @ idle.

    https://imgur.com/a/97g6sCU

MSI Afterburner (underclock to reduce heat or overclock to get that extra 2FPS)

    I've been stable @ 900/1800/950 for a while, albeit with an epic laptop pad YMMV

    https://www.msi.com/page/afterburner

I had problems with the 7.2.3 version of RTSS giving me 'unable to hook' errors, I use 7.2.2 instead, older versions are here:

    https://www.guru3d.com/files-details/rtss-rivatuner-statistics-server-download.html

Available via Manual Update

The chipset drivers above seem to work fine, if you like you can manually update the following. (Go to Device Manager and use the 'Search Automatically' option. For some reason Intel now dates their chipset drivers to 1968 so they won't over-ride existing drivers -- this is the work-around.

At the time of writing, the version for these is 10.1.1.38

    2nd generation Intel(R) Core(TM) processor family DRAM Controller - 0104

    Intel(R) 6 Series/C200 Series Chipset Family USB Enhanced Host Controller - 1C26

    Intel(R) 6 Series/C200 Series Chipset Family USB Enhanced Host Controller - 1C2D

    Intel(R) QM67 Express Chipset Family LPC Interface Controller - 1C4F

    2nd generation Intel(R) Core(TM) processor family PCI Express Controller - 0101

    Intel(R) 6 Series/C200 Series Chipset Family PCI Express Root Port 1 - 1C10

    Intel(R) 6 Series/C200 Series Chipset Family PCI Express Root Port 2 - 1C12

    Intel(R) 6 Series/C200 Series Chipset Family PCI Express Root Port 4 - 1C16

    Intel(R) 6 Series/C200 Series Chipset Family PCI Express Root Port 5 - 1C18

    Intel(R) 6 Series/C200 Series Chipset Family SMBus Controller - 1C22

Manuals & Utilities

T420/T421 User Guide

    https://download.lenovo.com/pccbbs/mobiles_pdf/t420_and_t420i_ug_en.pdf?linkTrack=PSP:ProductInfo:UserGuide

T420/T420i Hardware Maintenance Manual

    https://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles_pdf/t420_t420i_hmm.pdf

The elusive Hardware Maintenance Diskette v1.9 (this one works from W10)

    http://download.lenovo.com/ibmdl/pub/pc/pccbbs/mobiles/i7tm38us.exe

Lenovo Battery Firmware Update 1.16

    https://support.lenovo.com/us/en/downloads/ds001322

Lenovo Keyboard Test 4.7.0.8081

    https://support.lenovo.com/us/en/downloads/ds112679

OEM Info (.reg file) and various oemlogo.bmp versions

    https://www.dropbox.com/s/9l0aqd4t1221z69/OEM%20Info%20%2B%20Icons.rar?dl=0

Notes:

Rename the files when downloading to something besides the garbled Lenovo names.

Low volume: Control Panel -> Smart Audio -> Click headphone picture -> Disable "safety"

Lenovo Power Manager no longer supported, use Lenovo Vantage to set charge threshold.

IME Security Risk: Disable or leave as "unknown device":

    Ports (Com & LPT) -> Intel(R) Active Management Techology - SOL (Com5)

I didn't bother listing the cellular adapter, it took up the valuable mSATA slot.

Files mirrored to Dropbox for posterity, but with more coherent names than Lenovo's random-letter garbage. I tend to keep the Dropbox ones more up to date, because those are what I'm actually using, this post only gets updated on a when-I-get-around-to-it basis :)

    https://www.dropbox.com/sh/52058f3ewi1scpd/AADaW8QJbgR_Th1kNxl708E9a?dl=0

MY T420

4180CM6, upgrades:

    Seagate Barracuda 500G yeah, I know Seagate makes people cringe

    Kingston uv500 120G mSATA there are better ssds, but the port limits to SATA300 anyways

    135W T520 p/s overkill, but it was cheap on eBay

    16G 1600 DDR3 G.Skill Hacked bios allows 1600

    9C battery (0A36303)

    17-2760QM Definitely want ThrottleStop for this...

    GDC Beast with nVidia 1050ti

Changes:

    Grouped FN key items

    Added Throttlestop setup

    Added Modem

    Link to Hardware Maintenance Diskette

    Mirrored to Dropbox because sometimes stuff vanishes off Lenovo's site.

    Found a camera driver that works.

    Link to Windows driver database for HD 3000

    Link to manuals

    Synaptics Fingerprint Reader & UltraNav

    Oem Info & Logo

    Instructions for 'forcing' camera drivers, I had problems with even the MS ones in W10 1903

    New version of Synaptics driver (14 Aug 2019)

    Note about Lenovo Power Manager Version

    DVD drive missing DLL fix

    Switched broken Intel links to M$ update catalog ones

    Section about manually updatable system devices.

    Dire warnings about Conexant drivers and 20H2, checked other driver versions.