Adding coherent_pool to boot.cmd on Xenial Mate by Ayufan causes boot loop

[k_mp]

Hi,

Due to my external WiFi driver, I added,

Code:

coherent_pool=4M

in /boot/boot.cmd at the end of

Code:

setenv bootargs

and ran

Code:

$ sudo mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr

But after a restart, the Pinebook didn't load up anymore and stuck in the boot loop (hangs on the logo). I'm using the Xenial Mate by Ayufan (the original factory distribution). Is there any solution to solve it? I know how to restore it. But to get my external WiFi works, I also need to have coherent_pool.
Unfortunately, since the Pinebook stuck in the boot logo, I can't see any logs.