Use NetBSD.
It has amazing i386 support and doesn't drop platforms just because they're slightly inconvenient.
Firefox won't crash on you on i586 or older because we fixed the bug with ffmpeg.
It has great security (mandatory W^X), is lightweight, and a dedicated team of developers going back to 1993.
It's a little bit unfriendly to users, but mostly because it's very "bare". meaning it'd be very light on your hardware.
Biting the hand that feeds IT
