I have redirect the serial console port from UART2 to UART1 following this tutorial: https://docs.labs.mediatek.com/resource/linkit-smart-7688/en/tutorials/firmware-and-bootloader/bootloader-and-kernel-console.
The firmware is built success (there is several download error, but finally it's compiled successful after several times re-compile), however the 7688 DUO board WIFI LED keeps light after upgrading this firmware which means the linux kernal initialization is failure.
The compiled firmware bin file size is 2.8 M, which is totally different from the firmware (21M) dlownload from the office site.
What's wrong with the firmware compile from the source?