Problems with simultaneous firmware download using multiple MCU-Links

[stanley-kylee]

Hello.

I am trying to "simultaneously" download firmware to 4 MIMXRT1021 MCUs after connecting 4 MCU-Links to 1 PC.
However, problems often arise during this operation.

The working environment is as follows.

- JTAG : MCU-Link (V2.263) 4EA
- MCU : MIMXRT1021
- Tool : Redlink (crt_emu_cm_redlink.exe)
- Run command : " --flash-load-exec filepath -g --debug 2 --vendor NXP -p MIMXRT1021xxxxx --load-base=0x60000000 --ConnectScript RT1020_connect.scp --probeserial SN -CoreIndex=0 --flash-driver= -x FlashDriverFile --flash-dir Directory_1 --flash-dir Directory_2 --flash-hashing"

After creating a thread in C#, the above operation was simultaneously downloaded to 4 MCUs, and it was confirmed that it proceeded normally.

Sometimes problems arise here. If the firmware downloads to all four MCUs are "almost" simultaneous, there is no problem.
However, if even one of the four finishes first (approximately 2 to 3 seconds ahead), the connection with the Redlink server is disconnected, and firmware downloads of other MCUs are stopped.

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Nt: Loading 'file.bin' Binary 0x60000000 len 0x9E640
Nc: Opening flash driver MIMXRT1020-EVK_IS25LP064.cfx
Nc: Sending VECTRESET to run flash driver
Nc: Flash device supported (8MB = 128*64K at 0x60000000)
Nt: Writing 648768 bytes to address 0x60000000 in Flash
Pb: 1 of 1 ( 0) Writing sectors 0-9 at 0x60000000 with 648768 bytes
Ps: ( 0) at 60000000: 0 bytes - 0/648768
Ps: ( 2) at 60000000: 16384 bytes - 16384/648768

***** Another MCU's download completed or aborted with an error *****
(The above phrase is not the actual log content)

Ns: redlink server client - failed to receive response (to op 6) from server after 2000ms - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request (op 4) to server - timed out (rc 138)
Nc: After error Ee(FF). Redlink interface error 255. -
Nc: Failed to read address register in DAP - Ee(FF). Redlink interface error 255.
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Wc: failed to send op EraseSector message - rc Ee(FF). Redlink interface error 255.

Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Nc: Sectors written: 10, unchanged: 0, total: 10
Nc: Closing flash driver MIMXRT1020-EVK_IS25LP064.cfx
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Wc: failed to send op Terminate message - rc Ee(FF). Redlink interface error 255.

Pb: (100) Writing Flash ended with an error.
Ed:05: File 'file.bin' load failure: Ee(FF). Redlink interface error 255.
Pc: (100) Target Connection Failed
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Ns: redlink server client - failed to send request to server - timed out (rc 138)
Nc: error closing down debug session - Ee(FF). Redlink interface error 255.
Ns: redlink server client - failed to send request (op 27) to server - timed out (rc 138)

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# Question

1. Why are other download tasks forced to abort when one finishes first?
2. How to reliably progress concurrent download tasks?
3. In order to download as stable as possible, should I proceed with "sequential download" rather than simultaneous download?