@silvia I used QFlash_V6.9V_CN. I have Windows 10 pro.
Unfortunately, on both modems I get the below error:
[2024-06-10_19:20:22:126]AT+CFUN=1
[2024-06-10_19:20:22:126]+CME ERROR: 0
Please send me the QCN file for both modules (RM520N and RM521F) with the guideline. Thanks.