Do not turn off your computer or disconnect from the power source while updating the BIOS as this could harm your computer. During the update, your computer will restart and you may briefly see a black screen.

Before updating, please read the installation instructions and important information noted below.

Dell ChengMing 3990/3991 System BIOS

Restart required AUTO INSTALLED This file was automatically installed as part of a recent update. If you are experiencing any issues, you can manually download and reinstall.
This package contains the Dell system BIOS update. BIOS is a firmware package that is embedded on a small memory chip on the system board. It controls the keyboard, monitor, disk drives, and other devices. This update addresses the Dell Security Advisories (DSA). A security advisory is a statement when a security vulnerability impacts a product, and a remedy is available for the vulnerability.
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Fixes & Enhancements

- This release contains security updates as disclosed in the Dell Security Advisory DSA-2024-030. For more information, see Dell Security Advisories and Notices.
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Version

1.26.0, 1.26.0

Release date

11 Mar 2024

Download Type

System BIOS

Category

BIOS

Importance

Critical
Dell Technologies highly recommends applying this important update as soon as possible. The update contains critical bug fixes and changes to improve functionality, reliability, and stability of your Dell system. It may also include security fixes and other feature enhancements.
Available formats View Important Information
File Format: CPG BIOS Executable for Windows/DOS
File Name: ChengMing_3990_3991_1.26.0.exe
File Size: 30.4 MB
This is a large file. Depending on your connection speed, it may take some time to download.
Format Description:
This file format consists of a BIOS executable file. The Universal (Windows/MS DOS) format can be used to install from any Windows or MS DOS environment.
To ensure the integrity of your download, please verify the checksum value.
MD5:
96f6ab1354e4c976a9f5d82bf3a74a69
SHA1:
73b73463072a4d4a4a6c1409103467e29d134a22
SHA-256:
cefb0790aea146d5c8c7078fa2feaa9be858027213ba3ef6f0268c26408f0a67
File Format: BIOS Recovery Image File
File Name: BIOS_IMG.rcv
File Size: 30.38 MB
This is a large file. Depending on your connection speed, it may take some time to download.
Format Description:
This file format consists of a BIOS Recovery image file. This file is used for the System BIOS Recovery process to recover a system from a corrupted BIOS.
To ensure the integrity of your download, please verify the checksum value.
MD5:
4e1248b47fded40dafca03ebb1f3381f
SHA1:
84ab7390306896311764af1817462d160c76e0c2
SHA-256:
2a5de2ca98430823d4af1a4ba76e69ee49a1ec9a7ca0f2998ca67f6754f9d724

By downloading, you accept the terms of the Dell Software License Agreement.

Additional details

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- Do not power off the system until the process of updating the BIOS is completed.
- Once the BIOS is upgraded, you cannot downgrade the BIOS to earlier versions. BIOS downgrades are restricted when there are security updates and important fixes with earlier versions that impact the functionality of the system.
- BIOS updates take no more than 5 minutes to be installed on your system. You can install the updates in the background while using the system.
ChengMing 3990/3991
Updating the BIOS from Windows

Note 1: Before updating the BIOS, ensure that you suspend BitLocker encryption on a BitLocker-enabled system. If BitLocker is not enabled on your system, you can ignore this step. For information about how to disable BitLocker, see How to Enable or Disable BitLocker with TPM in Windows at support.dell.com.
Note 2: Do not turn off power or interrupt the BIOS update process during the update.
Note 3: Your system requires a restart after installing the BIOS. The restart can be deferred but must be completed to ensure that the update is installed.

Download and Installation
1. Click Download File.
2. Click Save to save the file to your hard drive.
3. Browse to the location where you downloaded the file.
4. Double-click the new file.
The system restarts automatically and updates the BIOS at the system startup screen. After the BIOS update is complete, system restarts again.

Updating the BIOS from BIOS Boot Menu (independent of operating system)

Note 1: Before updating the BIOS, ensure that you suspend BitLocker encryption on a BitLocker-enabled system. If BitLocker is not enabled on your system, you can ignore this step. For information about how to disable BitLocker, see How to Enable or Disable BitLocker with TPM in Windows at support.dell.com.
Note 2: Do not turn off the power or interrupt the BIOS update process during the update.
Note 3: Your system requires a restart after installing the BIOS. The restart can be deferred but must be completed to ensure that the update is installed.

Installation
1. Copy the downloaded file to a USB drive. You do not need a bootable USB drive.
2. Insert the USB drive into any USB port.
3. Power on the system.
4. At the DELL logo screen, press F12 to access the one-time boot menu.
5. Select BIOS Flash Update in the Other Options section.
6. Click the ... button to browse the USB drive to locate the downloaded file.
7. Select the file and click Ok.
8. Verify the existing system BIOS information and the BIOS update information.
9. Click Begin Flash Update.
10. Review the Warning message and click Yes to proceed with the update.
The system restarts and displays a Flash Progress bar at the Dell logo screen. The system restarts again when the Flash update is complete.

Need help with BIOS issues?

Find a solution in Dell's BIOS troubleshooting and usage guide.

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