Extended temp range, long-term supply, CE & FCC certification, BSP with OTA upgrade support, manufacturing tool, and best of all: "we rely on Neutis ourselves in our line of Reach M+ and Reach RS+ RTK GNSS receivers".
What WiFi+BT chip is used?
Webpage mentions Debian briefly. How good is that support today?
I will ask team about Debian tomorrow, can you get in touch with us directly so that we can keep this conversation going? You can find the contact email on Neutis website.
I am oversimplifying a bit, but you should be able to take these instructions [1], combine with a kernel and bootloader built for this board, and write the resulting image to eMMC/flash. You need to configure a few things correctly, boot cmdline & bootloader options but that's it.
Source: have used debootstrap to build custom distros for a couple ARM modules as well as x86.