Legion y740 doesn’t boot

[magic sand]

Hello!
Model: Legion y740 15irhg
I recently tried to tighten timings without increasing voltages of my RAM on my legion y740 15irhg through advanced bios. Memory fast boot was enabled and I think some important overtightened timings are not retraining, and I believe because of it laptop is constantly restarting and trying to retrain it (my assumption). But failing to retrain it doesn’t reset timings. I can’t get to bios and reset settings. Nor clearing CMOS helps default the BIOS settings. NOVO button does nothing either. Also, I tried removing RAM sticks on by one, changing slots. Fans stop working after few seconds and some retrain reboots are take longer before another reboot. Keyboard shortcuts like fn+q or fn+space do work tho. Previously it used to just black screen me once, then reset ram timings. Could I have kill my RAM or laptop:((?
Nothing is working so far, I can’t get to Lenovo boot logo.
Please help! 😭

[magic sand]

please help

[sage zephyr]

You probably will need to bring it to a store or flash the bios with external flasher

[magic sand]

Thank you for the response!
I’ll give a shot flashing the bios. Are there any guides on external flashing for the legion y740?

[sage zephyr]

Ask mitschud

[magic sand]

Ok, thank you!

[magic sand]

@tiny silo

[tiny silo]

First of all did you try this https://github.com/nonkerdoob/SmokelessCPU-Guides/blob/main/Guides/BIOS/BIOS_CRISIS.md

Also, if you have other kit, slot that one in, it will recover the timings, then ive seen discussions about how you put the bad ram into the free slot while the machine is running but

The thing is, even if you have spi flasher to reflash bios, what would you reflash it with? A broken bios you have now ? i assume you didnt even think about backing up the bios

[magic sand]

I haven’t tried it. Cool post. Gonna try tomorrow once I get my hands on the laptop

[magic sand]

I can download the bios from Lenovo website I believe

[tiny silo]

Thats the installer with patcher, not bios image you can flash

Bios image is "created" during flashing process

[magic sand]

Sorry man, it sounds little bit confusing. Does it mean I wouldn’t be able to do it?

[magic sand]

I don’t have the Image, I didn’t even know I could backup the bios

[magic sand]

Can’t I extract the contents of the installer, to get the .bin file?

I believe that’s how I downgraded my bios last time

[tiny silo]

Thats clean bios image, your pc wouldnt know if its legion 5 or 7, its serial num etc

Downgrading by exe is literally evoking the flashing process during which the image is recreated

If you flash the bios file from exe with external flasher, you might aswell sell your pc as russian legion bootleg for 50€

[magic sand]

😅

Doesn’t sound like a good perspective

[tiny silo]

Best bet

Or buy new preflashed y740 bios chip, desolder old, solder on new and pray it works

Good luck finding it

[magic sand]

Doubt that’s happening

[magic sand]

I’ll try this, love you man✊🏻

[magic sand]

Couldn’t make the last 2 steps, never started beeping :((

Are there no other ways other than spi programmer?:(

[tiny silo]

Nope, and again
"The thing is, even if you have spi flasher to reflash bios, what would you reflash it with? A broken bios you have now ? i assume you didnt even think about backing up the bios"

You have no backup to reflash the bios with

So basically your only real chance to recover this device is to find y740 bios backup on google and try to flash it with spi cha341a eeprom programmer

Then use LVAR to add serial number and stuff like that

I had this issue with y540 bios, had no backup, it was bricked. Found y540 bios on google and flashed it

Novo didnt work, ec reset or bios reset didnt work, bios crisis didnt work

Now you understand why we dont fuck with voltages in bios

[magic sand]

🥲

[magic sand]

The bios for my laptop from Lenovo, that I got using serial number not gonna work either?

Sorry, I’m didn’t quite the part, where I don’t have anything to flash it with

https://youtu.be/IqHAFk_Oy9Q
His method ain’t gonna work?

Or maybe using the spi programmer I could find the setting that corresponds to default settings and turn it on?

@robust sonnet

I ordered the flasher but it would arrive in mid January:(

[tiny silo]

Again, you need BIOS IMAGE THAT HAS BEEN PATCHED ONTO THE BIOS, NOT BIOS FILE THAT WILL BE USED DURING PATCHING, you CANT get that file

It has to be created ON THE MACHINE DURING THE PATCHING PROCESS

[scarlet knot]

honestly, keep trying

i did the same mistake, got my tertiary timings too low, same issue. although granted i have the L5 2020, it should still work on yours

took me around 20ish minutes of pain to get it right

or maybe even half an hour

... and the first thing i did after reviving my laptop from the dead was tightening the ram timings again

[magic sand]

so true, but I ended up contacting some service center where they put another BIOS chip with my BIOS installed. So its working now. Thank you anyway!

[tiny silo]

[magic sand]

Thank you for the support brother!

How can I backup my bios image, if smth similar happens I dont end up in such situation

[magic sand]

?

XD

[tiny silo]

lemme pack it

[magic sand]

it says cant identify bios

[tiny silo]

if the bar progress is stuck, just wait, the app is old

[magic sand]

it worked:)

how did you record your screen so fast in such good quality?

what software?

[magic sand]

So this is the image I would have to use to flash back to the chip using SPI Programmer if i mess up again right?

[tiny silo]

ye

[tiny silo]

obs studio

[magic sand]

Thank you once again! ✊🏻

@robust sonnet thank you too brother!✊🏻

[craggy venture]

you fool, this is for thaiphoon