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ULINK: How to downgrade the firmware of ULINK2/ME

Information in this knowledgebase article applies to:



ULINK2/ME is not detected by µVision or target debugging does not work any more after a firmware update of ULINK2/ME.


ULINK2 and ULINK-ME firmware updates have always been backward compatible to all previous µVision versions but unfortunately firmware version 2.01 is an exception. The firmware version 2.01 and later is now CMSIS-DAP compatible by default.

If ULINK2/ME was purchased after March 2013, it will already have firmware version 2.01 or higher. The ULINK2/ME firmware is updated to this version with these software packages:

  • MDK-ARM version 4.70 or higher
  • PK166 version 7.53 or higher
  • PK51 version 9.52 or higher

If you are unsure about the firmware version of your ULINK2/ME and you do not see it in the µVision dialog Options for Target - Debug - ULINK driver - Settings you can detect it by finding out the USB product ID. This page of our ULINK2 Trouble Shooting Guide shows how to do that.


Our Boot Mode Utility can switch from CMSIS-DAP to ULINK mode without replacing the ULINK2/ME firmware. This should solve almost all compatibility issues with older µVision versions. The UL2_Configure.exe utility is part of the attached ZIP file.

Only in very rare cases, it will be necessary to erase the firmware of ULINK2/ME so that an older firmware can be installed by an older µVision version. If this is necessary, please perform the following steps:

  • Download the file that is attached to this knowledgebase article and extract the ZIP file into a new folder.
  • Start UL2_EraseFW.exe and you should see a dialog open.
  • Select one of your connected ULINK2/ME in the Device list and press the Erase FW button.
  • Wait until you see the message Erase Done in the Status line.
  • Now you can open an older version of µVision. Performing any action with ULINK2/ME such as starting a debug session, starting a flash download or opening the ULINK settings dialog will download the corresponding firmware to ULINK2/ME.



Request the files attached to this knowledgebase article.


The following Discussion Forum threads may provide information related to this topic.

Last Reviewed: Tuesday, April 4, 2017

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