[TOOL] Lenovo (H20) Bios Unlocker and Locker

Hi please could you tell how did you managed to get it working on Legion 5 15ACH6H GKCN49WW

Thank you very much for quick reply

No problem. Good luck. Make Sure not to change any of the Memory Related Settings, or your BIOS will get bricked.

Would it be possible to increase the GPU power allotment while on battery with this? My legion 5 17 will pull a maximum of 40w while on battery or PD chargers. So my 100w charger will only pull like 65w since I disable CPU boost as well. Naturally an extra 20w on the gpu while on 100w charger would be pretty cool. I know it would tank battery performance pretty hard, but I never actually use it on battery anyways.

What additional settings did you guys unlock on Ideapad Gaming 3 82EY? Can you attach a photo?

You can try the LegionFanControl software. I has a dGPU TDP Boost, and a dGPU Power mode setting that lets you manually Enable or Disable the GPU boost. Give that a go, might work.

You can try the LegionFanControl software. I has a dGPU TDP Boost, and a dGPU Power mode setting that lets you manually Enable or Disable the GPU boost. Give that a go, might work.

what is thermal fan control under power? it was on disabled, i set it to Auto now (Lenovo Legion 5 15ARH05)
unlock worked (Bios FSCN13WW)

You can try the LegionFanControl software. I has a dGPU TDP Boost, and a dGPU Power mode setting that lets you manually Enable or Disable the GPU boost. Give that a go, might work.


As far as I can see, that just disables/enables dynamic boost. I’m looking to override the power limit on battery/PD charger. I think LFC isn’t quite deep enough to let me do that. Great software either way though.

For anyone else curious like me, it definitely looks like we can play with our power settings and change our gpu limits, with ac and dc power limits, but I truthfully don’t know these things well enough to change the settings on my own. But it does seem like what I want IS possible.

uh… Someone help please? I changed a couple settings and now in halo infinite I can hit 200 FPS. Before I was cpu bottlenecked to like 100-120fps, no matter how much I lowered my settings. This is insane. But I’m not 100% sure what I did was safe lol. Temps seems fine thats for sure.

What setting you changed?, I can tell you who is more or less safe.
Then depending on your dGPU you could also flash another vbios with higher TDP settings…

Is there a way to disable SPD write protection via an unlock like this? I’d like to mess around with the Memory Timings and Clock, but can’t because the BIOS gets bricked if I change anything, so I’d like to try with Thaiphoon.

So Cool, Thanks you ! Works perfectly for me now. But Mem overclock isn’t work. The DDR4 memory detection feature mentioned above was not found. Acer Triton500 has memory detection function, memory overclocking failure will automatically restore factory Settings, in order to try various memory parameter optimizations.

Edit: Just looking at the advanced menu, There are UMC Common Options/ Memory MBIST and Phy Configuration /PMU Training. Also similar to the Acer Triton500 memory self-check function, may be able to automatically recover the wrong memory parameters?

Advanced -> PCH-IO Configuration -> SPD Write Disable.

Advanced -> PCH-IO Configuration -> SPD Write Disable.


There is no such Options in my BIOS (Legion 5 15ACH6H GKCN49WW). I’ve been through all the settings but only found the above mentioned MBIST and PMU Training setting, however I dared not try to fiddle with them as I don’t currently have a spare computer to reflash my BIOS with my SPI Flasher.



Okay, so I took the risk and tried turning both these on, but it still won’t boot if I change any of the Memory Settings. Thankfully just disconnecting both batteries and my NVMe drives, managed to restore the BIOS. I feel safer now to experiment. LOL

Edit: Is there a way to update the AGESA in the bios with a mod?

Okay, I’ve done messed up haha. Can’t restore the bios with CMOS clear. Can someone please download the GKCN49WW bios for me, and extract the bios.fd from it so I can do the recovery from usb, please?

Here you, go already renamed with the proper name, just extract the .bin to the usb

you know the procedure?

gkcn.zip (5.59 MB)

Thank you for the quick help! Yes, it is already beeping like it should haha. Damn loud! Haha. For future reference, gkcn34ww version bios doesn’t seem to be able to restore itself for some reason. I was trying to play around with older versions maybe one would work for memory, but no luck.

Let me know if all is fine, once restore, I suggest to load default, and restore the PK, KEK etc … keys, form the security tab, as the laptop will be in Setup mode after that, instead of User mode.

Regarding memory, I think that the best thing to do, is find another laptop where these work, and compare the CBS/PBS settings…