S32K312 "cannot access memory" Error and Device Lock During Cyclone Flash Programming

[HaileyByun]

Hello,

We are experiencing issues while programming the S32K312 MCU using a Cyclone programmer. Our process requires the use of the memory swap feature, and our Cyclone script writes the images in the following order:

1. HSE image
2. FBL + RTSW image
3. FBL image for PartB area

During the flashing process, we frequently encounter a "cannot access memory" error, and sometimes the MCU becomes locked. This issue seems to occur especially after programming the HSE image.

We would like to ask:

• Is a full power cycle (complete power-off and power-on) strictly required after programming the HSE image?
• Are there any recommended flash sequences or precautions when using Cyclone scripts for S32K312, especially regarding HSE and memory swap?
• Are there any additional considerations when using the memory swap feature?
• If the MCU becomes locked, what are the recommended recovery methods (e.g., Secure Boot Recovery Tool)?

We would appreciate any official guidelines, recommended programming sequences, or troubleshooting advice you can provide.

Thank you.

[pearl44snow]

A full power cycle is not strictly required after programming the HSE image; a standard reset is generally sufficient. However, after installing an A/B swap version of the HSE firmware, two resets are needed for the firmware to be automatically copied to both active and passive partitions. The "cannot access memory" error and MCU lock issues are often caused by using an incorrect flash algorithm for the Cyclone programmer. You must select the specific flash algorithm that corresponds to your configuration (e.g., nxp_s32k312_1x32x424k_ab_swap.arp if memory swap is enabled) to ensure that the programmer doesn't overwrite the memory areas reserved by the HSE firmware. When using the memory swap feature, it is critical to wait until the HSE firmware has finished its backup to the passive partition after a swap, which can take up to a second. This is indicated by the HSE_STATUS_INIT_OK flag. If the MCU becomes locked, recovery methods depend on the specific lock state (e.g., if secure boot is configured). The Secure Boot Recovery Tool is one option, but success is dependent on the exact cause of the lock paybyplatema

[lukaszadrapa]

Hi @HaileyByun 

"During the flashing process, we frequently encounter a "cannot access memory" error, and sometimes the MCU becomes locked. This issue seems to occur especially after programming the HSE image."
- This seems to be the most important point. Did you select the right flash algorithm once HSE firmware is installed? You can take a look at:
https://www.pemicro.com/arm/device_support/NXP_Automotive/S32K3xx/S32K312/index.cfm
There are three algorithms:
nxp_s32k312_1x32x500k_hse_disabled.arp
nxp_s32k312_1x32x424k_ab_swap.arp
nxp_s32k312_1x32x456k_hse_enabled.arp
When HSE feature flash in UTEST is programmed, flash areas reserved for FULL_MEM version of firmware are removed from the memory map. Once AB_SWAP firmware is installed, additional area for active block is reserved in the memory.
Pemicro programmer needs to be informed about this - it's necessary to select the right algorithm. Then it will not touch those reserved areas.
Isn't this the root cause?

To answer your questions:

- Is a full power cycle (complete power-off and power-on) strictly required after programming the HSE image?
No, reset is sufficient. Notice that two resets are necessary after installation of AB_SWAP version because the firmware needs to be copied to both active and passive partition (it's done automatically).

- Are there any recommended flash sequences or precautions when using Cyclone scripts for S32K312, especially regarding HSE and memory swap?
It's necessary to select the right flash algorithm as mentioned above.

- Are there any additional considerations when using the memory swap feature?
After each swap, it takes about 1s to backup the HSE firmware to passive partition. Application (and also flash programmer in this case) should wait until this operation is finished (until HSE_STATUS_INIT_OK is set).

- If the MCU becomes locked, what are the recommended recovery methods (e.g., Secure Boot Recovery Tool)?
It depends what "locked" means. Does your application configure secure boot? Is ADKP set and is life cycle advanced? Are you able to establish a connection via your debugger?

Regards,
Lukas