bin/usb in hackmac-1.1.3 vs bin/usb in hackmac-1.2.0

@@ -10,10 +10,13 @@
 
 dev = File.basename(dev)
 
 mountpoint     = $config.usb.mp
 mountpoint_efi = '/Volumes/%s' % $config.devices.usb.name
+unless File.exist?($config.usb.os)
+  fail "Cannot find #{$config.usb.os.inspect}!"
+end
 
 ask("Really erase #{dev.inspect} and install #{$config.usb.os.inspect}? (y/n) ") or exit
 
 x %{diskutil partitionDisk #{dev.inspect} GPT JHFS+ "USB" 100%}
 
@@ -25,6 +28,7 @@
 cd mountpoint_efi do
   x %{sudo chown $USER .}
   x %{git init}
   x %{git remote add origin #{$config.efi.source.inspect}}
   x %{git pull origin master}
+  x %{git branch --set-upstream-to=origin/master}
 end