A cheap AUE Chromebook flashed with UEFI makes a good (albeit rather storage-starved) Linux beater - but you'll have trouble with Haiku or any of the BSDs because the hardware is a little "quirky." The input devices in most of the currently-cheap x86 Chromebooks are plumbed over i2c in a slightly strange way that didn't even work entirely right on mainline Linux until fairly recently, and Bay/Cherry trail style half-SOC-half-external-codec style sound hardware that only mostly works in mainline Linux right now.
Just because I was beating on it at the time, I tried Haiku and NetBSD on a Dell Chromebook 3189 2-in-1 with Mr. Chromebox Coreboot back in August, and (quoting myself from https://pappp.net/?p=59407 ) Haiku R1B4 boots but sees no integrated input devices or sound, Haiku Nightly hrev57235 sees the mouse (which is interesting because it looks like the patch adding support should have been in R1B4), but itβs constantly drifting and spamming click events, and still no keyboard or sound. NetBSD9.0 loses track of its discs during boot, while 9.3 boots but with no integrated mouse/keyboard β there are patches under review in July β23 to add support for them.
For about the same price as bare SBC or surplus SFF box, a hacked Chromebook gets you input devices, a display, a managed battery, and a usually rather rugged portable case, but no exposed GPIOs or UARTs or the like. For 3D printer controllers, streaming media endpoints, software experiments that might screw up the host so you don't want them on a machine you care about, and that sort of thing, they're a decent choice.
At least once one open-source OS supports a bit of hardware, the other ones can look in and see what they need to do. That doesn't prevent them from lacking the personpower to actually do it, but it drops the effort required to reverse engineer from scratch dramatically, if someone becomes interested enough.
Just because I was beating on it at the time, I tried Haiku and NetBSD on a Dell Chromebook 3189 2-in-1 with Mr. Chromebox Coreboot back in August, and (quoting myself from https://pappp.net/?p=59407 ) Haiku R1B4 boots but sees no integrated input devices or sound, Haiku Nightly hrev57235 sees the mouse (which is interesting because it looks like the patch adding support should have been in R1B4), but itβs constantly drifting and spamming click events, and still no keyboard or sound. NetBSD9.0 loses track of its discs during boot, while 9.3 boots but with no integrated mouse/keyboard β there are patches under review in July β23 to add support for them.
For about the same price as bare SBC or surplus SFF box, a hacked Chromebook gets you input devices, a display, a managed battery, and a usually rather rugged portable case, but no exposed GPIOs or UARTs or the like. For 3D printer controllers, streaming media endpoints, software experiments that might screw up the host so you don't want them on a machine you care about, and that sort of thing, they're a decent choice.