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Associate II
July 2, 2025
Question

STM32U5 encountering error DEV_TARGET_NOT_HALTED.

  • July 2, 2025
  • 3 replies
  • 1018 views

Hi All,

I have two questions:
1. Does the STM32U5 microcontroller support reversible RDP Level 2?

2. I have attached the steps we followed - it appears that RDP Level 2 is being unlocked, but afterward we are encountering a DEV_TARGET_NOT_HALTED.

Could someone please review the steps and helps us resolve the issue?

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This topic has been closed for replies.

3 replies

ST Technical Moderator
July 3, 2025

Hello @Gaurangthaker ,

Make sure to update the STLink version.

Please follow the steps and recommendation described in this article : How to regress from RDP level 2 to RDP level 0 on the STM32U5 series

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Associate II
July 4, 2025

Hi @Imen.D 

We have followed the same procedure and thoroughly reviewed each step. Additionally, my ST-Link firmware is up to date. Please let me know if there are any other steps I should follow to resolve the issue.

ST Technical Moderator
July 7, 2025

Did you try Connect Under Reset mode?

Refer to AN5347 and check the steps described in section '7 Readout protection (RDP) when TrustZone enabled'.

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In order to give better visibility on the answered topics, please click on 'Best answer' on the reply which solved your issue or answered your question. Thanks