Debug Port Inaccessible – MCU Issue, Not Boot

samjalkh — Mon, 09 Mar 2026 13:59:58 GMT

I’d like to share a problem I encountered while working with the EVK-MIMXRT1024 board.

This is not a boot loader issue – it’s an MU-level problem. When attempting to debug, I consistently get the following errors:

15: Target error from Read Memory
Debug port inaccessible after access at location 0x402D8004
Debug port inaccessible after access at location 0x402D8008
Debug port inaccessible after access at location 0x402D8010
Debug port inaccessible after access at location 0x402D8014
Debug port inaccessible after access at location 0x402D8024
Debug port inaccessible after access at location 0x402D8040
Debug port inaccessible after access at location 0x402D8044
Debug port inaccessible after access at location 0x402D8064
Debug port inaccessible after access at location 0x402D8084
Debug port inaccessible after access at location 0x402D80C4
Debug port inaccessible after access at location 0x402D80E4
Debug port inaccessible after access at location 0x402D80E8
Debug port inaccessible after access at location 0x402D80EC
Debug port inaccessible after access at location 0x402D80F0
Debug port inaccessible after access at location 0x402D8100
Debug port inaccessible after access at location 0x402D8118

Debugging context: evkmimxrt1024_hello_world Link Server Debug

The debug port becomes inaccessible after memory access attempts at specific addresses in O CRAM. This strongly indicates an MU-side fault rather than a boot loader misconfiguration

Re: Debug Port Inaccessible – MCU Issue, Not Boot

Gavin_Jia — Tue, 10 Mar 2026 02:14:50 GMT

Hi @samjalkh ,

Thanks for your interest in NXP MIMXRT series!

Did this issue occur during the debugging phase after you accessed a specific register address? However, based on the log, this address appears to be an ENET peripheral register rather than one in OCRAM. If that's the case, the discussion in this post may be helpful to you: https://community.nxp.com/t5/i-MX-Processors/Simple-question-regarding-memory-access/m-p/1575898

Best regards,
Gavin

topic Re: Debug Port Inaccessible – MCU Issue, Not Boot in i.MX RT Crossover MCUs

Debug Port Inaccessible – MCU Issue, Not Boot

Re: Debug Port Inaccessible – MCU Issue, Not Boot