Hello!
Basically I can’t use keyboard in my Lenovo legion y740 laptop. Friend of mine suggested this forum, since he couldn’t help me resolve my issue.
I have very little knowledge on BIOS and on how it works, but I wanted to optimize my laptop for maximum performance and minimum latency. So while messing around I changed some values I wasn’t sure about. I didn’t expect this outcome.
My system works fine, as well as OS. I can even boot into BIOS no problem. But BIOS doesn’t respond to my keyboard inputs at all. External keyboards don’t work either. My laptop also has NOVO button, which opens NOVO menu where users can perform system recovery or resets, but I can’t use it because it doesn’t respond to my inputs.
I tried to power drain the motherboard so it would reset. I tried to reset BIOS by unplugging Laptop battery and CMOS battery from motherboard and held the power button. I left it sit for 10 minutes, 30 minutes, 8 hrs, and even one day. BIOS wouldn’t reset.
I also tried reinstalling BIOS, but I unfortunately I have latest version of it. Even if I bypass BIOS version check, changing values in platform.ini it wouldn’t help. I doubt Lenovo will publish a new BIOS for this laptop, even if they did I can’t wait.
Friend of mine, tried to modify somekinda existing var.txt and then rewriting, then installing it. I believe the software has to do smth with Insyder H2O. But I may be mistaking.
He tried to enable BIOS USB support, but it didn’t work. He also tried to load default setup, didn’t work either. So I’m here. I feel uncomfortable in such advanced forum as I might not understand most of the stuff. I’m the simplest laptop user basically.
I would appreciate any help, thank you
Laptop: Lenovo Legion y740 15IRHg
BIOS version: 1.10
Provide the mod/changes "…So while messing around I changed some values I wasn’t sure about.", that u made to bios and how flashed
@Daniyar1997 - Does the trackpad still work? Does mouse still work? << If yes to either, in BIOS? If yes, load optimized defaults and reboot, if that does not fix the issue it’s not BIOS related.
Have you been inside the laptop lately? If yes, maybe loose cable to KB, or disconnected cable to KB?
Try this >> Remove HDD/SSD, remove ALL memory, remove Main battery, remove PSU Cable. Then press and hold the case power on switch for 10-15 seconds, let sit for few minutes with no power
Then connect PSU cable only and try to boot it AS-IS w/ no HDD/SSD and NO memory, let it run for a minute or two. Then shut down and put back in one stick of memory, boot to BIOS, can you then load optimized, reboot and use KB?
Did you have unlocked BIOS? If not, I find it very hard to believe there is any way you can disable mouse from the BIOS, stuff like that is hidden in normal BIOS, so must be some other issue here.
What did friend modify in Vars? What was disabled that he enabled, specifically? Ask him if you do not know. Also, provide me with the vars.txt before and the modified vars he had you flash back.
And, what didn’t work about this? Nothing was fixed, or you could not flash back the modified vars?
Since you can navigate around to dump and flash vars, I assume something is working. Can you try to flash current or one previous version BIOS from within windows?
And, the most important question, to lighten the mood here!! >>>
How is the performance & latency now? 
J/K, but kinda not, curious if your other changes helped you achieve what you wanted 
My mood is really great now! We managed to resolve the issue, the options he changed in vars.txt didnt help resolve the issue of no response to keyboard. But then he also allowed bios back flash, and removed bios lock I believe. So I could simply downgrade bios and it has set to defaults. It happened like 20 mins earlier. I really appreciate your interest and willingness to help. But the issue is resolved now. 
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Btw is there any good BIOS optimization guide tho? Because I might have messed up, but I’m still willing to squeeze most of my laptop.
@Daniyar1997 - Great to hear you were able to get this sorted out!! 
Sorry, not sure about any guides, you’ll have to google around and see what you can find