diff --git a/contrib/containers/guix/scripts/guix-start b/contrib/containers/guix/scripts/guix-start
index f36674427d..1b5e75b5e7 100755
--- a/contrib/containers/guix/scripts/guix-start
+++ b/contrib/containers/guix/scripts/guix-start
@@ -12,6 +12,7 @@ fi
 XCODE_VERSION="12.2"
 XCODE_RELEASE="12B45b"
 XCODE_ARCHIVE="Xcode-${XCODE_VERSION}-${XCODE_RELEASE}-extracted-SDK-with-libcxx-headers"
+XCODE_SOURCE="${XCODE_SOURCE:-https://bitcoincore.org/depends-sources/sdks}"
 
 export SDK_PATH="${SDK_PATH:-${WORKSPACE_PATH}/depends/SDKs}"
 
@@ -19,7 +20,7 @@ export SDK_PATH="${SDK_PATH:-${WORKSPACE_PATH}/depends/SDKs}"
 if [[ ! -d "${SDK_PATH}/${XCODE_ARCHIVE}" ]]; then
     echo "Preparing macOS SDK..."
     mkdir -p "${SDK_PATH}"
-    curl -L https://bitcoincore.org/depends-sources/sdks/${XCODE_ARCHIVE}.tar.gz | tar -xz -C "${SDK_PATH}"
+    curl -L "${XCODE_SOURCE}/${XCODE_ARCHIVE}.tar.gz" | tar -xz -C "${SDK_PATH}"
 fi
 
 # Add safe.directory option only when WORKSPACE_PATH was specified via cmd-line arguments (happens in CI)