diff --git a/apps/ios/build-rust.sh b/apps/ios/build-rust.sh
index 1135cc8e524153f5cac29e60545866846f138740..881673e3981aeb2639cc17583db12fc91e8ae982 100755
--- a/apps/ios/build-rust.sh
+++ b/apps/ios/build-rust.sh
@@ -10,7 +10,7 @@ release=
 root="$SRCROOT/../.."
 # Xcode's SDK variables would point host build scripts at the iOS SDK.
 exec env -i HOME="$HOME" PATH="$HOME/.cargo/bin:/etc/profiles/per-user/$USER/bin:/run/current-system/sw/bin:/usr/bin:/bin:/usr/sbin:/sbin" USER="$USER" \
-	CARGO_TARGET_DIR="$root/target/ios" IPHONEOS_DEPLOYMENT_TARGET="$IPHONEOS_DEPLOYMENT_TARGET" \
+	CARGO_TARGET_DIR="$root/target/ios" CARGO_BUILD_JOBS="${CARGO_BUILD_JOBS:-2}" IPHONEOS_DEPLOYMENT_TARGET="$IPHONEOS_DEPLOYMENT_TARGET" \
 	sh -ec '
 		python3 "$1/tools/cargo_fresh.py" --target "$2" $3
 		exec cargo build --manifest-path "$1/Cargo.toml" -p mobile --target "$2" $3