diff --git a/support/download/cargo-post-process b/support/download/cargo-post-process
index b94b160315..a9fbced466 100755
--- a/support/download/cargo-post-process
+++ b/support/download/cargo-post-process
@@ -5,10 +5,12 @@ set -e
 # shellcheck source=helpers source-path=SCRIPTDIR
 . "${0%/*}/helpers"
 
-while getopts "n:o:" OPT; do
+manifest="${BR_CARGO_MANIFEST_PATH-Cargo.toml}"
+while getopts "n:o:m:" OPT; do
     case "${OPT}" in
     o)  output="${OPTARG}";;
     n)  base_name="${OPTARG}";;
+    m)  manifest="${OPTARG}";;
     :)  error "option '%s' expects a mandatory argument\n" "${OPTARG}";;
     \?) error "unknown option '%s'\n" "${OPTARG}";;
     esac
@@ -29,7 +31,7 @@ mkdir -p .cargo/
 mkdir -p "${CARGO_HOME}"
 flock "${CARGO_HOME}"/.br-lock \
 cargo vendor \
-    --manifest-path "${BR_CARGO_MANIFEST_PATH-Cargo.toml}" \
+    --manifest-path "${manifest}" \
     --locked VENDOR \
     > .cargo/config