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Paper Tape
Posts: 1
Registered: ‎09-27-2016
Location: US
Views: 601
Message 1 of 3

T440s won't load any Win OS after BIOS update

Hi, a couple of days ago I let Lenovo Assistant perform four automatic updates, critical, as they were pointed – three driver updates and the BIOS. As I noticed, the BIOS was updated with the help of BIOS update utility, the system restarted correctly and flashed the downloaded image. Now it’s shown in BIOS setup window to be a current version - GJET90WW UEFI BIOS, GJHT29WW ECP. Previously it was a version of 2.36 package.

The system boots, but the OS (Win7 x64) stops loading on Win logo after this BIOS update. While loading in the safe mode it stops on classpnp.sys

Unfortunately no other Win OS (Win XP, Win 8, Win 10) or pre-installation environment (win 8 PE, win 10 PE) could be loaded - the same problem. No way out except turning of the notebook with the power button (even pressing emergency reset button has no result). The system hangs.

I've tried doing all the stuff with removing the internal and external batteries, extra memory, SSD, loading from USB with/without SSD, from external CD, rescue disks, forums of classpnp.sys load problems  etc. Except trying to load Linux.

Besides, I’m unable to reset any previous version of BIOS with the help of BIOS Update Bootable CD (If the UEFI BIOS has been updated to version 2.40 or higher, it is no longer able to roll back to the version before 2.40 for security improvement)…


Does anyone have an idea how to do?



P.S.     SSD is ok, fortunately I’ve got my files from it on another PC.

            Lenovo diagnostics and system tests are fine. BIOS setup is available for any changes.  

Paper Tape
Posts: 2
Registered: ‎03-31-2015
Location: TR
Views: 544
Message 2 of 3

Re: T440s won't load any Win OS after BIOS update

Hi Ptig,


I have same problem with you and I had almost same steps with you but couldn't solve problem yet. Found a lot of information about classpnp.sys but any of them didn't help me out. 


Did you solve your problem? Can you share if you find any working solution? 


Thank you so much.


Paper Tape
Posts: 2
Registered: ‎03-31-2015
Location: TR
Views: 534
Message 3 of 3

Re: T440s won't load any Win OS after BIOS update

Hi again,


I found solution right after my post. It's a common problem and there are official and unofficial solutions.


I followed the steps at below solve my problem. 


Change the BIOS Setup to disable Execution Prevention setting:

  1. Power on the system and press F1 key to enter the BIOS Setup.
  2. Move to the Security page and goes to the Memory Protection subpage.
  3. Change Execution Prevention to Disabled.
  4. Press F10 to save and exit the BIOS Setup. Then, boot to the operating system.

You can read related article here:


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