diff --git a/packages/master/src/routes.js b/packages/master/src/routes.js
index 0843f79a..b6d7f741 100644
--- a/packages/master/src/routes.js
+++ b/packages/master/src/routes.js
@@ -259,6 +259,11 @@ async function getStream(req, res) {
 }
 
 
+const zipMimes = [
+	"application/zip",
+	"application/x-zip-compressed",
+];
+
 async function uploadSave(req, res) {
 	try {
 		res.locals.user.checkPermission("core.instance.save.upload");
@@ -319,7 +324,7 @@ async function uploadSave(req, res) {
 					requestErrors.push("instance_id must come before files uploaded");
 				}
 
-				if (fileMime !== "application/zip") {
+				if (!zipMimes.includes(fileMime)) {
 					requestErrors.push("invalid file Content-Type");
 				}
 
@@ -350,7 +355,7 @@ async function uploadSave(req, res) {
 			req.pipe(busboy);
 		});
 
-	} else if (mimeType === "application/zip") {
+	} else if (zipMimes.includes(mimeType)) {
 		let filename = req.query.filename;
 		if (typeof filename !== "string") {
 			requestErrors.push("Missing or invalid filename parameter");
diff --git a/test/master/routes.js b/test/master/routes.js
index 7037be75..cca2c3b7 100644
--- a/test/master/routes.js
+++ b/test/master/routes.js
@@ -325,5 +325,25 @@ describe("master/src/routes", function() {
 			assert.deepEqual(JSON.parse(response.body), { saves: ["test.zip"] });
 			assert.equal(response.statusCode, 200);
 		});
+		it("should complete a valid transfer with non-standerd mime type", async function() {
+			master.forwardRequestToInstance = async (request, data) => {
+				let stream = await phin({
+					url: `http://localhost:${port}/api/stream/${data.stream_id}`,
+				});
+				assert.equal(stream.body.toString(), "totally a zip file");
+				return { save: data.filename };
+			};
+			let response;
+			response = await phin({
+				url: `http://localhost:${port}/api/upload-save?instance_id=123&filename=test.zip`, method: "POST",
+				headers: {
+					"X-Access-Token": testToken,
+					"Content-Type": "application/x-zip-compressed",
+				},
+				data: "totally a zip file",
+			});
+			assert.deepEqual(JSON.parse(response.body), { saves: ["test.zip"] });
+			assert.equal(response.statusCode, 200);
+		});
 	});
 });