The manifest is untrusted input. It is now read under a size limit and
validated before use: destinations are contained below the BIOS root,
repo_path stays inside bios/, release_asset is a basename, hashes match
their shape, declared totals match their lists, and every entry has a
download source.
Downloads stream against the declared size, are checked by SHA-256 then
SHA-1, land in a per-process temporary file and are installed with
os.replace. Copies into standalone-emulator directories are opt-in with
--standalone-copies so a detection never writes outside the selected
tree.
Both bootstraps verify install.py against an embedded SHA-256 before
running it, and require the Python version install.py actually needs.
A target that publishes no core list is a target with no filter, not a
broken manifest: rejecting it disabled --target for the whole platform.
Abdessamad Derraz