EC200U boot loop

I wrote some faulty RTOS code while developing software for the UART interface. Now the EC200U module reboots every couple of seconds. This is too rapid for the QFlash to detect the boot mode.

Looking into the QFlash user guide, I see “You can also upgrade EC200U by short-circuiting BOOT to PL_1V8 to get the SPRD U2S Diag port loaded for upgrade.”

I tried to locate these two pins in UMTS-LTE_EVB_User_Guide_V2.1, but I can’t find the pins. I only found USB_BOOT and VDD_1.8V on J805. Are these the same pins that the QFlash user guide was referring to? If not, could you please post labelled pictures pointing to the right pins on the EVB?

I’m re-confirming because there is a mismatch between the documents, and I don’t want to damage the hardware by shorting the wrong pins.

Also, is this the only way to fix a boot loop, or is there some other way?

Hi there,
If you have our EVB, you can short-circuiting BOOT to PL_1V8, it will enter download mode when it is powered on. IF you only have our EC200U module, you can pull up USB_BOOT to 1.8 V before VDD_EXT is
powered up, and the module will enter download mode when it is powered on. In this mode, the module
can upgrade firmware over USB interface. The USB_BOOT pin is 115.