log used 'a' in both MBR and GPT, but it should be 'an MBR'
@ -386,7 +386,7 @@ def gpt_device(dev_name):
"""
is_gpt = osdriver.gpt_device(dev_name)
config.usb_gpt = is_gpt
gen.log('Device %s is a %s disk.' % (dev_name, is_gpt and 'GPT' or 'MBR'))
gen.log('Device %s is %s disk.' % (dev_name, is_gpt and 'a GPT' or 'an MBR'))
def unmount(usb_disk):