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 OptiPlex 990 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 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

- Updated to the latest CPU microcode to address CVE-2017-5715 and associated Intel Reboot issue.
Read More

Version

A23, A23

Release date

07 Mar 2018

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: O990-A23.exe
File Size: 5.59 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:
10a056c2f872a4a52a009f0d2281bb02
SHA1:
b75181724c13fefead328ba4caa292e55f6b5dc2
SHA-256:
21adcb687d53461bcc2cd10cab76f860b73f72c8d70452a9c7b25b5805cec8b7

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

Additional details

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If the BIOS version that is installed on your system is A04 or any previous versions, you must upgrade the BIOS to version A05 before installing this package.
If the BIOS version that is installed on your system is A05 or later versions that are released before A10, you must upgrade the BIOS to version A10 before installing this package.
Dell Optiplex 990
Updating the BIOS from Windows

Note 1: Before updating the BIOS, ensure that you suspend BitLocker encryption on a BitLocker-enabled system. If it 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.

Download and Installation
1. Click Download File, to download the file.
2. Click Save to save the file to your hard drive.
3. Browse to the location where you downloaded the file and 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 DOS (Non-Windows users)

Note 1: Before updating the BIOS, ensure that you suspend BitLocker encryption on a BitLocker-enabled system. If it 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.

Installation
Note: You must provide a bootable USB drive. This executable file does not create the DOS system files.
1. Copy the downloaded file to a bootable USB drive.
2. Power on the system and then Press the F12 key.
3. Select USB Storage Device and boot to the DOS prompt.
4. Run the file by typing following command. For example:
C:\ Precision_5530_X.Y.Z.exe
Where C is the drive letter of the USB device where the executable file is located and Precision_5530_X.Y.Z.exe is the name of the downloaded file.
The system restarts automatically and updates the BIOS at the system startup screen. After the BIOS update is complete, system restarts again.

Need help with BIOS issues?

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

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