Can a BIOS be restored using a USB flash drive?
Can a BIOS be restored using a USB flash drive?
Hello
The ThinkBook 14 G4 2-in-1 with an Intel Core Ultra 7 155U is functioning properly until a Windows update installed a new BIOS version, changing it from P3CN46WW to P3CN48WW. Following this change, the machine began requiring at least 30 seconds on a black, illuminated display before displaying the Lenovo logo. This delay was quite bothersome and extended the boot time unnecessarily.
To resolve the issue, I attempted to downgrade the BIOS. I disabled the "Prevent BIOS Downgrade" setting and also turned off BIOS Self-Healing, as each successful downgrade would trigger an automatic upgrade after the second reboot. Now, the downgrade process runs smoothly from 1% to 100%, but upon rebooting it displays 0% and then loops indefinitely, with the power button light blinking six times each time it is turned off. I have reset the CMOS battery several times and even removed the main battery, but nothing resolved the problem.
My final option was to enter Crisis Mode. According to various forums, the correct key combination is Fn + R while connecting the power cable, using a USB drive formatted to FAT32 with the BIOS file. When this method is used, the laptop powers on, the keyboard lights up, the Caps Lock indicator remains active, and the charging LED turns orange—even when the battery is full. However, no beep sounds are heard, which typically signals a BIOS flash. The CPU and fan operate normally, but the process seems stuck.
Attached are some photos and videos illustrating the problem. Any assistance would be greatly appreciated.
https://imgur.com/qP666qV
View: https://imgur.com/qP666qV
https://imgur.com/jwf32xQ
View: https://imgur.com/jwf32xQ
https://imgur.com/mdr6j7v
View: https://imgur.com/mdr6j7v
https://imgur.com/06ngfe9
View: https://imgur.com/06ngfe9
The laptop functioned properly until a Windows update introduced a new BIOS version, changing it from P3CN46WW to P3CN48WW.
https://pcsupport.lenovo.com/hk/en/produ...7A93E0428C
It seems the BIOS version you referenced isn't listed, possibly because it was based on the laptop's model. You may receive a more precise response by entering your laptop's serial number on Lenovo's support site. If a BIOS update is present, you might have updated it yourself after launching the installer with administrator privileges.
Following the update, the device required at least 30 seconds on a darkened screen before displaying the Lenovo logo. This delay was quite bothersome and extended the boot time unnecessarily.
I would have kept it unchanged, as downgrading BIOS often leads to hardware failure or damage.
Consider unplugging the laptop from the power source, shutting it down, removing the battery, and then pressing the power button for 30 seconds to discharge any remaining charge. Reconnect to a proper power adapter (not the battery) and try restarting the device to see if it powers up successfully.
As a final option, you could use a CH341A BIOS programming tool and flash the BIOS with the latest version, as suggested here:
https://www.reddit.com/r/thinkpad/commen..._flashing/
Additionally, if the laptop is still under warranty, reaching out to Lenovo or your seller would be advisable to clarify the issue.
The unusual thing is that I’m not sure how the BIOS was updated via a Windows update. When the laptop restarted, it displayed a message asking it to be plugged in to finish the BIOS update correctly.
But when I looked at the Windows Update history, there was nothing about a BIOS update.
Here are images showing the BIOS version before and after the update:
https://imgur.com/rMwjYxc
View: https://imgur.com/rMwjYxc
https://imgur.com/m9f9lyO
View: https://imgur.com/m9f9lyO
I can leave this mode by pressing the power button for roughly thirty seconds. Then the laptop begins restarting the bootloop once more—displaying the BIOS update at 0%, followed by shutting down and restarting again. I attempted to replace both the CMOS battery and the main battery, but it didn’t resolve the issue. The laptop kept looping through the same reboot sequence even when connected to a charger. I shared this experience because I believed the device might have a hidden BIOS recovery option, as discussed in several forums. This capability is reported to function on Lenovo Legion and Ideapad models.
https://www.reddit.com/r/LenovoLegi..._p..._with_usb/
https://www.reddit.com/r/Lenovo/comments...o_ideapad/
https://www.bios-mods.com/forum/Thread-M...-IMPORTANT
Hello, I understand you're dealing with BIOS problems. I resolved a similar long boot time issue on my Thinkbook 14 g7 by accessing BIOS - Security - Reset System to Factory Defaults. This reduced my boot time from over 50 seconds to just 18 seconds.
Code analysis shows:
systemd-analyze results: 18.975s total
Comparable case: system upgraded to BIOS version 48 despite only listing 46 on Lenovo's site.
It really slows things down (33 seconds) due to dual boot. However, when just Windows was installed, it took about 20 seconds, which is similar to Manjaro. I didn't mention that I initially turned off Windows fast boot, disabled hibernation, and then in BIOS pressed F9 - load defaults; none of these steps helped. It wasn't until I selected "BIOS - Security - Reset System to Factory Defaults" that the laptop restarted and began booting more quickly. Before that, I experienced a black screen lasting 20-30 seconds, after which the Lenovo logo appeared.
Manjaro in dual boot setup
Before "BIOS - Security - Reset System to Factory Defaults"
Code details:
Startup duration was 47.519 seconds.
After the update, it reduced to 18.975 seconds.
This change mainly impacted the firmware loading time before the system logo appears.