Firefox has been able to run on RISC-V for as long as I can remember. I'm pretty sure I remember SiFive doing a demo back in 2018 at FOSDEM which included the browser. However generally GUI environments are still quite slow, so it won't be very usable.

Edit: This one I think: https://archive.fosdem.org/2018/schedule/event/riscv/ but I can only see them running Quake, not Firefox.

Firefox is on Debian riscv64, but Chromium is a lot less portable, and IIRC often rejects portability patches.

https://buildd.debian.org/status/package.php?p=firefox%2desr https://buildd.debian.org/status/package.php?p=chromium

The latest Ubuntu image for the P550 has Firefox installed.

https://github.com/sifive/hifive-premier-p550-ubuntu/blob/ma...