@Pali, patches 0001-mtd-fix-a-huge-latency-problem-in-the-MTD-CFI-flash-.diff and 0002-mtd-change-struct-flchip_shared-spinlock-locking-int.diff are still enabled in series file, please disable them as it is confirmed those cause reboots/slowdowns.

Also I am unable to use QtMobileHotspot with USB, device reboots in 1-2 seconds after connecting USB cable. Please anyone to test if it is working for him with latest KP. I suspect it might be USB sysfs notify patch, will disable it and will test.

EDIT:
it is not USB sysfs notify which bugs the kernel.