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 Pro Tower QCT1255/Slim QCS1255/Micro QCM1255 System BIOS
Restart required 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.
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Fixes & Enhancements
Fixes:
- Fixed the issue where the Enable UEFI Capsule Firmware Updates option is not displayed in the BIOS Setup.
- Fixed the issue where a USB keyboard or mouse does not work in the BIOS Setup.
- Fixed the issue where the Dell Premier Rechargeable Wireless Mouse MS900 does not work in the BIOS Setup.
- Fixed the issue where you cannot update the BIOS through the exe installation. This issue occurs on systems with the Serial Card and Parallel Card configuration.
- Fixed the issue where an error message is displayed when you enable the DASH Support. This issue occurs after the system resumes from modern standby, hibernate, and shut down.
- Fixed the issue where the system LED is on when you disable the Integrated NIC option.
- Fixed the issue where the system cannot boot to the iPXE server when you enable the DASH Support.
- Fixed the issue where Bluetooth cannot be detected in BIOS or Onboard Diagnostics, after setting a system HDD or SSD password with a WLAN card installed.
- Fixed the issue where the Type-C module firmware displayed as 0.0.0.0 after updating to BIOS version 1.3.2.
- Fixed the issue where the system cannot boot. This issue occurs after you set the admin password in the BIOS Setup and perform a Real-Time Clock (RTC) reset.
- Fixed the issue where you cannot perform the BIOS Recovery. This issue occurs after you set the admin password in the BIOS Setup and perform a Real-Time Clock (RTC) reset.
- Fixed the issue where the system cannot boot and the system LED displays four amber and two white lights. This issue occurs on Dell Pro Micro QCM1255 systems.
Enhancements:
- Updated the firmware of HDMI and DisplayPort option modules to the latest version during the BIOS update.
- Enabled the SATA hard drive function on Dell Pro Tower QCT1255 and Slim QCS1255 systems.
Read More- Fixed the issue where the Enable UEFI Capsule Firmware Updates option is not displayed in the BIOS Setup.
- Fixed the issue where a USB keyboard or mouse does not work in the BIOS Setup.
- Fixed the issue where the Dell Premier Rechargeable Wireless Mouse MS900 does not work in the BIOS Setup.
- Fixed the issue where you cannot update the BIOS through the exe installation. This issue occurs on systems with the Serial Card and Parallel Card configuration.
- Fixed the issue where an error message is displayed when you enable the DASH Support. This issue occurs after the system resumes from modern standby, hibernate, and shut down.
- Fixed the issue where the system LED is on when you disable the Integrated NIC option.
- Fixed the issue where the system cannot boot to the iPXE server when you enable the DASH Support.
- Fixed the issue where Bluetooth cannot be detected in BIOS or Onboard Diagnostics, after setting a system HDD or SSD password with a WLAN card installed.
- Fixed the issue where the Type-C module firmware displayed as 0.0.0.0 after updating to BIOS version 1.3.2.
- Fixed the issue where the system cannot boot. This issue occurs after you set the admin password in the BIOS Setup and perform a Real-Time Clock (RTC) reset.
- Fixed the issue where you cannot perform the BIOS Recovery. This issue occurs after you set the admin password in the BIOS Setup and perform a Real-Time Clock (RTC) reset.
- Fixed the issue where the system cannot boot and the system LED displays four amber and two white lights. This issue occurs on Dell Pro Micro QCM1255 systems.
Enhancements:
- Updated the firmware of HDMI and DisplayPort option modules to the latest version during the BIOS update.
- Enabled the SATA hard drive function on Dell Pro Tower QCT1255 and Slim QCS1255 systems.
Version
1.4.2, 1.4.2
Release date
16 Jul 2025
Download Type
System BIOS
Category
BIOS
Importance
CriticalDell 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: Dell_Pro_QCT1255_QCS1255_QCM1255_1.4.2.exe
File Size: 23.16 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:
ad9f7d472a8bd9f722d57e8bed35159d
SHA1:
94fbcae388fb5aceeecefde72b9e4f1cf896e282
SHA-256:
6fbd8cc2c4a3a7f478defa7a69210076aabf08e973721d8065e4604a457e8af8
File Format: BIOS Recovery Image File
File Name: BIOS_IMG.rcv
File Size: 23.15 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:
360aef57502339060a26519a8e6de265
SHA1:
089db153c744f2c496cd49cbc793420598e1fcff
SHA-256:
3718411c5fcc1c9ca7b10587c805a25d891ff56c791a94be9302ba2d36d09436
By downloading, you accept the terms of the Dell Software License Agreement.
Important Information
- Do not power off the system until the process of updating the BIOS is completed.
- This BIOS contains the new 2023 Secure Boot Certificates.
- 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.
- This BIOS contains the new 2023 Secure Boot Certificates.
- 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.
Applies to
Dell Pro Micro QCM1255 system BIOS
Dell Pro Slim QCS1255 system BIOS
Dell Pro Tower QCT1255 system BIOS
Installation instructions
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.
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 guideDrivers help and tutorials
For more downloads go to the Drivers and downloads. For help on using the information on this page, please visit Driver Help and Tutorials.