Wi-Fi 5Ghz troubles.

[Desperanto86]

Hi! I have next issue:
I have Wi-Fi router ASUS RT-N66U with 2 bands 2,4Ghz & 5Ghz. They have auto channels (13/14 for 2.4Ghz and 161 for 5Ghz).
Now, when I put out sim cards from the phone, the last see all wi-fi spots and work with them perfect! When I insert sim carsd to the phone (I've tried many sims), the last is turning on, connecting to my 5Ghz wi-fi for about 30 seconds and then phone can't see and connect to my 5Ghz wi-fi... Phone can see 5Ghz wi-fi only on 36 and 136 channels. By the way Sony Bravia Android TV 2015 can't work on 136 channel and with 36 channel connect of TV not stable. 2.4Ghz works fine, but I need 5Ghz!
This issue 100% in software. Because without sims all work perfect! I think android 6 have some regional limits.
But without root I can't remove regional limits
Can any one give some advices?
By the way: region Russia, all devices for our region and was bought in official stores.

[MarlonUk1]

have you tried it while you are in safe mode?

as you have mentioned the problem only appears if you insert the simcards , did you buy the devices from a network? if yes they must have some software modifications on the devices.

try asking around XDA forums for more information

[Desperanto86]

Device is general = not locked, not for special  network. I have"Bootloader unlock allowed YES". Safemode have tried - the same trouble: without sims all ok, with sims only 36 channel work. The tourble comes immediatly after fresh flashing with full wiping (firmware from XperiaFirm for RU region).