Comment 37 for bug 1711337

Thanks for providing the stack trace, Lars.

This shows the illegal instruction is happening in Skia, specifically SkJumper's implementation of _sk_xor__vfp4. To run with Skia disabled, edit your user profile at ~/.mozilla/firefox/*.default/prefs.js and add the following line:

user_pref("gfx.content.azure.backends", "");

Firefox 32-bit will then launch on Raspbian Stretch. Or if you have more than one user, you can instead edit /usr/lib/firefox/defaults/pref/vendor-gre.js

I expect rendering performance is taking a hit with Skia disabled. For a proper fix we should figure out what's going on with the illegal instruction(s) in SkJumper_generated.S. This file is auto-generated so from what I can tell the armv7 version isn't readily available via git. I have yet to set up a build environment for Firefox, but if someone here has done so for Arch Linux and another for Ubuntu, we can diff and track this down.