I have run SpiderOak this way, which is about the only thing I've run into that was both closed-source and non-ARM, and it worked but was painfully slow because SpiderOak is just an intense app. Smaller tests using hugo (a golang static site generator) binaries were quite pleasing though.
It's been a bit since I did this but I didn't use an alternate root filesystem and instead used debian's multiarch support -- IIRC there's even package support that sets up binfmt_misc for you.
Check out https://wiki.debian.org/QemuUserEmulation
It has some outdated info now, I believe you can stop reading at "That's it." Oh, and when adding a new arch and pulling libraries for it, you need to use "i686" or "amd64" since this was written for someone who wants to run emulated armhf binaries.
It's been a bit since I did this but I didn't use an alternate root filesystem and instead used debian's multiarch support -- IIRC there's even package support that sets up binfmt_misc for you.
Check out https://wiki.debian.org/QemuUserEmulation
It has some outdated info now, I believe you can stop reading at "That's it." Oh, and when adding a new arch and pulling libraries for it, you need to use "i686" or "amd64" since this was written for someone who wants to run emulated armhf binaries.