Symptoms
Affected Platforms:
- Inspiron 14 5441
- Inspiron 14 Plus 7441
- Latitude 5455
- Latitude 7455
The Dell flash program displays, Error: Firmware update from revision to 2.6.0 is not permitted. The system is configured to block firmware updates to previous revisions, when attempting to run BIOS v2.6.0 flash package after setting Allow BIOS Downgrade to disable in the BIOS menu.
To Reproduce:
- Disable Allow BIOS Downgrade in BIOS menu (default is enabled).
- Boot to the operating system and run v2.6.0 BIOS flash program (the error message is displayed).

Cause
Caused by Dell Firmware Updater (DFU) tool leads to Downgrade Denial.
Resolution
Do not dispatch hardware for this issue.
You can resolve this by doing one of the following:
- Use Windows Update instead of the Dell BIOS 2.6.0 flash package.
Or,
- Enable Allow BIOS Downgrade before BIOS 2.6.0 exe flash package is run from Windows.

Affected Products
Inspiron 14 5441, Inspiron 14 Plus 7441, Latitude 5455, Latitude 7455