@felix - Probably 2-4 bytes edited, that’s usually all you need to change on Insyde BIOS to unlock BIOS menus
Dudu2002 is over at BIOS-mods.com forum if you wanted to talk to him about it, or have him unlock for you, but you need flash programmer like CH341A + SOIC8 test clip with cable and then dump your BIOS and send to him then he will unlock for you.
Hello,
Thank you for your reply. I have sent PM to him previously, i am just using my device constantly and cannot find time to disassemble it and do the procedure.
@felix - You’re welcome! If you want, and he hasn’t replied, link me to your latest BIOS download at Lenovo site and I will see if I can do the edit for you.
Sometimes I can do, if I can see correct edit location, but Insyde BIOS beats me sometimes 
But, even if I do it, you will need to dump and send me the file so I can apply the edit then you program back.
Also, sometimes there may be a way around that without programmer, but I’ll have to look at BIOS settings, and then we’ll have to try something and see outcome! 
@Lost_N_BIOS
Thank you very much, i appreciate your kind offer.
Previously (when i tried to unlock DMI3.0 for having full speed of my NVMe SSD) i had done some trials with h2OUVE etc.
If you would like to take a look, i have attached full UEFI Protocol Menu and current Bios i am running (Lenovo Download extracted in .fd form, not dump from actual system), in the zip below :
Y700-17ISK_CN53_UEFI.zip (4.18 MB)
@felix - You’re welcome! Please link me to the BIOS download page from Lenovo as I asked, thanks, this is all i need.
DMI3 thing, if it’s a BIOS setting, we can change without flashing or making mod BIOS, same way we will possibly disable FPRR to bypass 167 error
@Lost_N_BIOS
I have version CDCN53WW, no longer available for download, but i believe that if you change the verison from the current bios download link, you can download it also :
https://download.lenovo.com/consumer/mobiles/cdcn54ww.exe
The Full download page is as follows :
https://pcsupport.lenovo.com/us/en/produ…nloads/DS112253
As for DMI setting, i have changed it on the fly, using UEFI Variable Editor utility. I did it some months after purchase and was the best mod possible for this laptop.
Previous zip file also has a .txt file with the UEFI variable menu, i believe i had extracted it with UEFI Tool 0.25.0 if i remember correctly.
@felix - yes, thanks, https://download.lenovo.com/consumer/mobiles/CDCN53WW.exe gives the version you mentioned
I checked, 167 is not set via BIOS setting 
Finally, i found time and disassembled my laptop to get a dump from Bios ic.
There are 2 SPI ic’s in the back of the board (the side facing to the back side of the keyboard, you need to get the board out completely).
One Winbond 25Q32FVS1Q, which returned a dump file of 4.00MB and full of FF’s. Obviously this is not needed, unless by programmer could not read that correctly.
The other one is a GigaDevice GD25Q64CSIG, which returned a dump file of 8.00MB and of various content.
I flashed the bios of the YouTube guy but found that the ME is initialized. I had to dump the ME from my machine’s bios, clean it and flash it before my system was responsive again. I’m also going to have to edit the DMI info and replace it with my machine’s.