Open-source, alternative firmware

Hi guys,

I’m considering getting a bunch of hAP ac boards to replace aging hardware on a number of installations. One thing that I require is full control of the software stack: I build the firmware from scratch (using buildroot in general).

How is this going to work with MikroTik devices? Is this RouterOS thing based on Linux? If so can I find the kernel patches, drivers, device tree somewhere?

Cheers,

You cannot do this with RouterOS.
You may be able to install alternative firmware from other sources and do what you want, but be careful
as the amount of flash storage has been reduced recently on entry-level devices, and while it is still
(barely) enough for RouterOS it may be too small for other images until they have adapted to the situation.

Depends upon the device and what you need. You can squeeze openwrt, for example, just by installing necessary packages (SW).
Then you will need to build your own image, for real downsizing.
Not all MTs run openrwrt, BTW.
openwrt is open, RoS is not.
openwrt the best choice for hotspots, for example.