Can I run my i386 binary on OpenBSD/amd64?
No. OpenBSD/amd64 is a totally separate platform from OpenBSD/i386, and at this point, no binary compatibility is provided. As OpenBSD encourages open source applications, there is not much interest in binary compatibility across platforms with developers. Note that the OpenBSD/amd64 and OpenBSD/i386 boot loaders will load each other’s kernels, making it easier to reinstall a system with the “other” platform. However, it has to be a complete “wipe and reinstall” operation — left-over binaries from the “previous” installation will most likely make your life unpleasant.