µVISION DEBUGGER: "Internal DLL Error" During Flash Programming

Information in this knowledgebase article applies to:

• Keil MDK 5.23
• ULINKpro Debug Adapter

SYMPTOM

I'm using ULINKpro on an existing project created by previous Keil MDK 5. 

After upgrading to Keil MDK 5.23, during flash programming, I always get the following errors:

Erase Done.
Programming Failed!
Internal DLL Error
Error: Flash Download failed - "Cortex-M3"

I didn't modify any project or debug settings of this project. 

How can I resolve this issue?

CAUSE

Such an issue happens when using ULINKpro in Keil MDK 5.23 in the following cases:

RESOLUTION

This issue has been fixed in MDK newer than 5.23.

Keil MDK 5.23 users may download the attached zip file containing the updated DLLs and replace them into:
[installation_path]\ARM\BIN\
Where [installation_path] is wherever you installed the Keil MDK tools. The default [installation_path] is: C:\Keil_V5.

ATTACHED FILES

Request the files attached to this knowledgebase article.

Last Reviewed: Thursday, November 5, 2020