diff --git a/templates/qemu.sh b/templates/qemu.sh
old mode 100755
new mode 100644
index 7cfeec4..77ddd69
--- a/templates/qemu.sh
+++ b/templates/qemu.sh
@@ -25,7 +25,7 @@ display none # Already handled by SPICE
 
 # NIC: attach to bridges:
 {% for br in c.bridges %}
-nic bridge,br={{ br.name }},model=virtio-net-pci,mac=52:54:00:17:{{ '%02x%02x' % (c.num, br.num) }}
+nic bridge,br={{ br.name }},model=virtio-net-pci,mac=52:54:00:17:{{ '%02x:%02x' % (c.num, br.num) }}
 {% endfor %}
 '