Comment 9 for bug 1499342

This smells like a modem FW issue: whatever the trick O2/symio are using to allow this kind of roaming, the modem does not like it unless the SIM has previously registered to that network. Not sure if we can do much there but complaining to MediaTek. However, the logcat might be useful to gather more information:

sudo /system/bin/logcat -b radio

Output of the command while scanning the operators would be interesting.

Another question, do you have roaming status when registered to the O2 network (for BQ and Meego)?