Bluetooth.start_scan() on Sipy new firmware

[maku]

As a test to get the bluetooth going I use a simply script like:
<code>
from network import Bluetooth
bluetooth = Bluetooth()
bluetooth.start_scan(3)
while bluetooth.isscanning():
adv = bluetooth.get_adv()
if adv:
print(adv[4].decode('hex'))
</code>

Whenever I run, pretty much anything involving decode method Pymakr stops responding until terminated.
Replacing print line with Print('Sucess') works as intended.
Reset in terminal doesn't resolve it.

Any help appreciated.