Can the stage1 wasm binary be reproduced by the stage2 or stage3 executable? Aside from a "trusting trust" type of attack that seems fine, and every modern distro relies on some bootstrap binary for C compilers anyway (usually older versions of them), so it wouldn't be that much different of a bootstrapping problem than bootstrapping GCC itself. (See the GNU Mes project which attempts to bootstrap from just a very small hex interpreter)