PowerEdge: 14G BIOS downgrade fails with UEFI0305 error

Summary: BIOS downgrading is blocked for certain memory configurations to prevent a system stop caused by a microcode issue in older versions.

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
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Symptoms

When trying to rollback a 14G BIOS to a previous version, it fails with the following error message:
 

 

UEFI0305: Unable to update BIOS firmware in the previous boot (Error Code = 0000000000000200)
Retry the operation. If the issue persists, contact your service provider.

 

Cause

With 14G servers, once BIOS version 1.4.5 or newer is installed, BIOS downgrade is blocked for certain memory configurations (18 nm technology RDIMMS), to prevent a system stop caused by a microcode issue in BIOS versions 1.1.7 or older. BIOS version 1.2.11 or newer is required to support the new 18 nm technology RDIMMs. PowerEdge C4140 servers are unaffected by this issue since all the released BIOS versions contain the corrected microcode.

 

Note: Even though the PowerEdge C4140 BIOS does contain the microcode that fully supports the 18 nm technology RDIMMs, BIOS versions 1.2.4 through 1.2.7 incorrectly set the associated BIOS flag that prevents the downgrade or update to a BIOS that does not have that BIOS flag set. PowerEdge C4140 BIOS version 1.6.11 removed that BIOS flag since it was technically not needed. If all three conditions listed in the resolution are met, customers attempting to update from BIOS version 1.2.4/1.2.6/1.2.7 to version 1.6.11 or higher fail with this same error message. The solution of how to update to 1.6.11 or newer in this case is the same as shown below.

Resolution

 BIOS version 1.4.5 or newer blocks BIOS downgrade if all three of the following conditions are met:

  • At least one 16GB RDIMM is installed that uses the new 18 nm technology (see vendor part-number examples below)
  • Memory is populated in a two DIMMs Per Channel (2DPC) configuration (any black connector populated, more than six DIMMs per CPU)
  • System memory speed is 2666 MT/s
Note: Starting with BIOS version 1.4.5, BIOS downgrading requires the Dell Update Package (DUP) to be installed from the OS or from iDRAC. The UEFI BIOS update tool no longer allows BIOS downgrading.

If a BIOS downgrade is required, and 18 nm 16DIMMs are installed, one of the following three actions are needed:

  • Reduce system memory speed to 2400 MT/s or 2133 MT/s, or
  • Remove DIMMs to get the system into a 1DPC configuration, or
  • Remove all DIMMs using 18 nm technology

Micron 18 nm 16GB DIMMs have been shipping into Dell factories since January. Samsung 18 nm 16GB DIMMs started shipping to Dell factories in March.

The 18 nm 16GB DIMMS can be identified by looking at the PartNumber field in the iDRAC UI - System -> Inventory -> Hardware Inventory and expand out the DIMM information:

iDRAC UI - System  

This example shows a Micron 16GB DIMM. PartNumber 18ASF2G72PDZ-2G6D1 is the part number for a 20 nm DIMM. The 18 nm Micron DIMM PartNumber is: 18ASF2G72PDZ-2G6E1

For a Samsung 16GB 20 nm DIMM, the PartNumber displayed would be M393A2K43BB1-CTD. The 18 nm Samsung DIMM is PartNumber: M393A2K43CB1-CTD

 

Affected Products

OEMR R240, OEMR R340, OEMR R440, OEMR R540, OEMR R640, OEMR XL R640, OEMR R6415, OEMR R740, OEMR XL R740, OEMR R740xd, OEMR XL R740xd, OEMR R740xd2, OEMR R7415, OEMR R7425, OEMR R840, OEMR R940, OEMR R940xa, OEMR T140, OEMR T340, OEMR T440, OEMR T640 , OEMR XL T640, OEMR XL R240, OEMR XL R340, Poweredge C4140, PowerEdge C6420, PowerEdge FC640, PowerEdge M640, PowerEdge M640 (for PE VRTX), PowerEdge R240, PowerEdge R340, PowerEdge R440, PowerEdge R540, PowerEdge R640, PowerEdge R6415, PowerEdge R740, PowerEdge R740XD, PowerEdge R740XD2, PowerEdge R7415, PowerEdge R7425, PowerEdge R840, PowerEdge R940, PowerEdge R940xa, PowerEdge T140, PowerEdge T340, PowerEdge T40, PowerEdge T440, PowerEdge T640 ...
Article Properties
Article Number: 000067023
Article Type: Solution
Last Modified: 09 Sep 2026
Version:  9
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