Compiling ARMv7 on dragonboard410c

It is written in the dragonboard410c spec that it supports also arm 32.
Is it possible to use the code in working/qualcomm/kernel.git - Qualcomm Landing Team kernel
to compile the kernel for arm ? and if so, what should be the $ARCH and the $CROSS_COMPILE ?

Possible but only in the sense that it is “just software”; there are no instructions for acheive it and this mode of operation is not supported.

In generally if you want to run 32-bit ARM applications you are better off using a 64-bit kernel with 32-bit syscall support (I think the DB410C kernel will already have this enabled).

I think you could either install a 32-bit rootfs or, if you configure apt properly, pull in just the 32-bit libraries you need (same as 32-bit support on x86-64).