Not sure of the hardware specifics, but “ARM” is not saying anything significant. You have to see if the specific processor used has mainline support in the present or in a past kernel that you can use.
For instance, Android is a scheme where google takes a Linux kernel, strips absolutely everything they can out if it and documents thoroughly. All the thing can do is run the app environment, but the kernel is incomplete with no hardware support. All the manufacturer must do is add the hardware support modules at the last possible moment. This makes it possible for manufacturers to only add binary support modules. The entire arrangement is designed to exploit the end user with these orphaned kernels and hardware you can never own. The hardware is undocumented anywhere, and each device is different enough that reverse engineering one will do nothing for supporting the next.
I’m not saying your device has an orphaned kernel, but this is what to look for in any device. Mainline kernel support means full ownership. Proprietary is always theft of ownership.