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
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.
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