Hello Quectel support / community,
I am facing a recovery issue with an EC200U module and need guidance.
Module details:
Model: EC200UEUAA-N05-SGNSA
Platform: Unisoc 8915DM (EC200U series)
What happened:
I accidentally flashed EC200U-CN firmware onto this EC200U-EUAA module.
After that, the module stopped working normally
Recovery attempt:
I can still access the device in download mode:
Device detected in Windows as: SPRD U2S Diag (COM50)
QFlash V7.3 successfully detects the device
I flashed official EU firmware:
8915DM_cat1_EC200UEUAAR03A23M08.pac
Flash process completes successfully (PASS every time)
Current behavior after flashing:
No USB devices appear in Windows in normal boot mode
No AT / modem ports show up
Only USB_BOOT mode exposes SPRD U2S Diag
Power consumption:
~70–100 mA during boot attempt
drops to ~17 mA
repeats in a loop
What I tried:
Reflashing multiple times (always PASS)
Different USB ports and cables
Power cycling and waiting for enumeration
Using correct EUAA firmware from Quectel support
Question:
The firmware flashes successfully, but the module does not boot into normal mode or expose USB interfaces.
Could this be caused by:
NV / calibration corruption from CN → EU firmware mismatch?
Wrong EUAA firmware revision (R03 vs earlier base versions)?
Need for full erase / factory reset before flashing?
Missing factory NV restore package?
Any guidance on recovery steps would be appreciated.