diff --git a/keepkeyctl b/keepkeyctl
index b6d105a8..113af94a 100755
--- a/keepkeyctl
+++ b/keepkeyctl
@@ -297,7 +297,7 @@ class Commands(object):
             raise Exception("Must provide firmware filename or URL")
 
         if args.file:
-            fp = open(args.file, 'r')
+            fp = open(args.file, 'rb')
         elif args.url:
             print("Downloading from", args.url)
             resp = urllib.urlretrieve(args.url)
@@ -316,8 +316,9 @@ class Commands(object):
             fp_old.close()
 
         fp.seek(0)
-        if fp.read(4) != 'KPKY':
-            raise Exception("KeepKey firmware header expected")
+        magic = fp.read(4).decode("utf-8")
+        if magic != 'KPKY':
+            raise Exception("KeepKey firmware header expected. magic={}".format(magic))
 
         print("Please confirm action on device...")