Hi,

This guide will, hopefully, help you Flash your BIOS using a USB Flash Drive without having to boot into your OS.

This process is useful in case your BIOS has been corrupted. 

• Maybe you tried updating your BIOS using an incompatible BIOS version.
• Maybe the BIOS Update process failed or was interrupted midway through.

A corrupted BIOS will prevent your system from booting into your OS

This process is intended for the Y540. Other laptop models may require a slight modification in some of the steps.

1- Prepare USB Flash Drive

• Connect an empty USB Flash Drive to your PC              (we will format it; all data will be lost)
• Open Command Prompt (CMD) as Administrator

• Type the following commands
  • Diskpart
  • List Disk
  • Select Disk #                             (Replace # with the number corresponding to your Flash Drive)
  • Clean                                          (You may repeat this command until it's successfully executed)
  • Convert GPT
  • Create Partition Primary
  • Format fs=FAT32 Label=BHCrisis
  • Assign
  • Exit
  • Exit

2- Download BIOS file

• Go to Lenovo Support page for Y540
• Enter your Y540 Serial Number                               (SN can be found on the bottom cover of Y540)
• Under "Manual Update", choose "BIOS/UEFI"
• Download the "BIOS Update" (exe) file

3- Extract BIOS Files                                                    (You need a file compression software such as WinRAR, PeaZip, 7-Zip, WinZip, etc.)

• Run the downloaded BIOS file, e.g. "BHCN38WW.exe", as administrator
• Follow instructions
• Deselect "Launch Lenovo BIOS Update Utility now"
• Finish
• Open "C:BIOSBHCN##WW" folder
• Right click "BHCN##WW.exe" and select "Extract to BHCN##WW"
• Open the extracted "BHCN##WW" folder
• Copy "BIOS.fd"
• Paste "BIOS.fd" to your USB Flash Drive
• Rename "BIOS.fd" to "BHCrisis.bin"

4- BIOS Settings

• Connect the USB Flash Drive to the Y540
• Press the power button on the Y540

• As soon as you see the "Legion" logo, keep tapping the "F2" key
  • (Alternatively, you can enter BIOS by pressing the "NOVO Button" which located between the USB port and power LED on the right side of the Y540)

• Go to "Configuration" tab
  • Set "BIOS Back Flash" to "Enabled"

• Go to "Boot" tab
• Make sure that your Flash Drive is recognized

• Select your Flash Drive and tap "F6" until it's atop the list
  • If you don't see your Flash Drive, enable "Legacy Support"
    • BIOS ⮕ Boot ⮕ Boot Mode: Legacy Support
  • Tap "F10" to save changes and exit
  • Enter BIOS again and make sure you see your Flash Drive and move it atop of the list
  • Tap "F10" to save and exit

• Power down the Y540

5- Clear CMOS Battery

• Power down the Y540
• Remove the AC adapter cable
• Remove any devices connected to the Y540
• Remove the screws of the bottom cover of your Y540
• Pry open the cover-- carefully
• Make sure you 'ground' your body to get rid of any static electricity
• Carefully remove the battery cable connector
• Carefully remove the CMOS battery connector
• Press and hold your laptop power button for 45 seconds
• Reconnect the CMOS battery-- carefully
• Leave the laptop battery disconnected
• Put back the bottom cover of your Y540

6-Enter Crisis/BIOS Recovery Mode

• Connect the Flash Drive to the Y540
• Press and hold the "Fn" and "R" keys
• While holding the "Fn" and "R" keys, connect the AC adapter cable to the Y540

• Wait for a while until you hear the Y540 'beeping'-- short and long 'beeps'
  • The sound is loud
  • You'll see the power button LED blinking
  • Y540 will power on and off before 'beeping'

• Release your hold of the keys after a few seconds of 'beeping'
• This process can take one or several minutes to complete
• Y540 is supposed to shutdown, and power back on when the BIOS Flashing is complete.
• Done!

7- Verify BIOS Version

•  
• Enter BIOS
• Make sure that the BIOS version on the "Information" tab reflects the BIOS version you downloaded from Lenovo Support
• BIOS ⮕ "Configuration" tab ⮕ "BIOS Back Flash: Enabled"
• Tap "F10" to save and exit

8- Boot into Windows

• Hopefully you'll be able to boot into Windows normally
• I recommend flashing BIOS again; this time from Windows
• Plug in the Y540 to the AC adapter
• Run the "BHCN##WW.exe" as administrator and follow the steps
• Y540 will reboot, complete BIOS Flashing, shutdown, and boot back up again.

I hope this detailed guide has helped you.

*Note: You can't run downloaded BIOS file from an incompatible laptop; you'll get an error message.

Links:

• Guide with screenshots and text files.
• BHCN38WW.exe (from Lenovo Support) (to be extracted using file compression software)

Hi I can't access to the bios anymore after disabled usb boot lan boot and intel gpu (I feel soooo dumb rn😢) I already try to remove the cmos battery whith the jumper for reset the bios but it didn't work 
Then i tried to use a usb flash drive I follow tour instructions and when I pressing th Fn+R + power button the ac indicator flash but nothing else happens no bip please help

Edit: here a link to my post on a subreddit 

https://www.reddit.com/r/24hoursupport/comments/i46ps9/hi_i_cant_access_to_the_bios_anymore_after/?utm_medium=android_app&utm_source=share

Edit I fixed it by using the crisis bios Recovery method 😃

This is the ".bin" file for BIOS version 38

For easy access

Hi, I'm trying to get this working at the moment, but when I get to step six I run into an issue. I have the flash drive connected and when I plug in the power cord while holding the FN and R keys, nothing happens. No beeps and no blinking power LED. Does anyone have any suggestions for other things to try?

Clearing cmos battery by openning laptops is important?

I have warranty for the next 1 year and i don't like open laptop

HELP!

Hi Mate , 

Can you please me the same way to Lenovo Ideapad 330s

I bricked my Ideapad by downgrading the BIOS for unlocking the wifi card, my stupidity 

Now laptop's display doesn't turn on, only power led, fans run in the background .

after seeing your detailed procedure, I got some confidence that my laptop may come back to normal.

My laptops Bios file link, 

https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/300-series/330s-14ikb/downloads/ds502884

how to extract the recovery file name from the official file and is the process the same for My model too ..

Please do the needful, WFH due to pandemic and stuck with this stupidity and the location where i stay doesn't have proper Lenovo service center

Thanks,

Karthik 

Hi I followed your steps but with 39 bios it installed but after install it stuck on boot and went to the blue critical process died screen. It went to preparing repair and it finished diagnostics then it told me did not start correctly there was restart and advanced options. What should I do next?