Boot sources missing on mangOH Yellow

I am currently trying to use the accelerometer to wake the board from ULPM.
I used the example code from the ShakeNWake demo and adapted the GPIO number to match the one used on mangOH Yellow (GPIO21).

However GPIO21 is not listed in the available boot sources of the board:

# ls /sys/module/swimcu_pm/boot_source/
adc     clear   enable  gpio36  gpio38  timer

Yet GPIO21 is labeled as “Wakeable” in the mangOH Yellow Schematic.

Is it normal ? Can I add this GPIO as a boot source myself ?

Thank you for your time, have a good day !

Okay I read the wp77xx Technical Specification and it says only GPIO 36 and GPIO38 are usable to wakeup from ULPM.
GPIO21 can only wake the device from Sleep State.

I thought the Sleep State was the same as Low Power Mode, but it’s not : the Sleep State is a Low-Power active state which require the module to be fully powered.

But this means you can’t use the accelerometer interrupt to wakeup from ULPM on a mangOH Yellow without modifying the BMI160 driver ?
Current driver configuration uses only the INT2 pin of the driver, which is linked to GPIO21 on mangOH Yellow…