diff --git a/lib/tessel/deploy.js b/lib/tessel/deploy.js
index 62835225..29ef9f73 100644
--- a/lib/tessel/deploy.js
+++ b/lib/tessel/deploy.js
@@ -311,7 +311,7 @@ actions.tarBundle = function(opts) {
   if (opts.slim) {
     logs.info('Generating slim build.');
     return new Promise(function(resolve, reject) {
-      actions.glob(target + '/**/*.tesselignore', {
+      actions.glob(target + path.normalize('/**/*.tesselignore'), {
         dot: true,
         mark: true,
       }, function(error, ignoreFiles) {
@@ -334,13 +334,14 @@ actions.tarBundle = function(opts) {
 
           return rules.concat(patterns);
         }, []).map(function(rule) {
-
+          // Ensure it uses proper paths for OS
+          rule = path.normalize(rule);
           if (rule[rule.length - 1] === '/') {
-            rule += '**/*.*';
+            rule += path.normalize('**/*.*');
           }
 
           if (rule[rule.length - 1] !== '*' && rule.indexOf('.') === -1) {
-            rule += '/**/*.*';
+            rule += path.normalize('/**/*.*');
           }
 
           return rule;
diff --git a/test/unit/deploy.js b/test/unit/deploy.js
index cc4416ce..ecec983e 100644
--- a/test/unit/deploy.js
+++ b/test/unit/deploy.js
@@ -387,17 +387,17 @@ exports['tarBundle'] = {
       // The comment line MUST NOT create a pattern entry.
       test.equal(this.globSync.callCount, 4);
       test.deepEqual(this.globSync.args, [
-        ['a/**/*.*', {
-          cwd: 'test/unit/fixtures/ignore'
+        [path.normalize('a/**/*.*'), {
+          cwd: path.normalize('test/unit/fixtures/ignore')
         }],
-        ['mock-foo.js', {
-          cwd: 'test/unit/fixtures/ignore'
+        [path.normalize('mock-foo.js'), {
+          cwd: path.normalize('test/unit/fixtures/ignore')
         }],
-        ['nested/b/**/*.*', {
-          cwd: 'test/unit/fixtures/ignore'
+        [path.normalize('nested/b/**/*.*'), {
+          cwd: path.normalize('test/unit/fixtures/ignore')
         }],
-        ['nested/file.js', {
-          cwd: 'test/unit/fixtures/ignore'
+        [path.normalize('nested/file.js'), {
+          cwd: path.normalize('test/unit/fixtures/ignore')
         }]
       ]);