A month ago, we formally announced that we were working to bring Firefox to ARM64 Windows. The last month has seen significant progress on our journey to that release.

The biggest news is that we have dogfoodable (auto-updating) Nightly builds available! As that message states, these Nightlies are even nightlier than our normal Nightlies, as they have not gone through our normal testing processes. But Firefox is perfectly usable on ARM64 Windows in its present state, so if you have an ARM64 device, please give it a try and file any bugs you find!

Since that announcement, native stack unwinding has been implemented. That in turn means the Gecko Profiler can now capture native (C++/Rust) stack frames, which is an important step towards making the Gecko Profiler functional. We also enabled WebRTC support, even though WebRTC video not working on ARM64 Windows is a known issue.

We’re currently working on porting our top-tier JavaScript JIT (IonMonkey) to ARM64. We’re also working on enabling the crashreporter, which is a pretty important feature for getting bug reports from the field! From my low-level tools perspective, the most interesting bug discovered via dogfooding is a WebRender crash caused by obscure ARM64-specific parameter passing issues in Rust itself.

Ideally, I’ll be writing updates every two weeks or so. If you see something I missed, or want to point out something that should be in the next update, please email me or come find me on IRC.

Tags: arm64, firefox, windows