2 66i trashed with FW update ?

You have to remove the device from Garmin Connect and the Bluetooth settings on the phone, restart the phone, AND remove the phone from the device and restart the device, then do a new Bluetooth Pairing.

Simple as that.

simple?

it took me with one 66i abt 40mins to get the BT connection, with the other one some 20min

Garmin Explore is searching and searching...

The important thing here is to be sure that BOTH ends fully forget one another. I believe that the 66i appears twice in the BT device list on the phone. This represents 2 separate connections. Nobody knows why. You need to forget BOTH of them from the phone side.

The relationship between GCM and Explore keeps changing. Before attempting to re-pair, make sure that neither GCM nor Explore remembers the device.

I did completely removed all traces of the 66i on the phone and fully reset the 66i so no traces of the phone were present.

However, when the phone is trying to pair with the 66i, it first searches for the 66i for long time. Then it starts to attempt the connection and 66i will display the code.

Entering this code will result in some 'failed' message and the whole procedure starts again. 66i will agai presnet a code which will fail again etc.

This takes me in average 10-15 times to enter the code and long 'search' in between.

66i appears not twice in my case when connection finally established

You have to first pair it Garmin connect and after with Garmin explorer 

we are talking abt FW 8.80, this is not done thin way there, only one app needed

skyeye Hello, with the new software update you no longer have to pair through garmin connect mobile first to pair the unit to your phone. You would want to remove all connections on the device (forget phone) and in your phone's bluetooth settings forget the device. Once you have done that put the device into pairing mode and then pair it directly through the garmin explore app on your phone. 

all known and all done this way

But it still needs countless tries until it is paired, when paired all is OK appart from the sync 66i-phone is very slow.

Pairing is a pain, the code given by the 66i is entered into the phone, but it is in general rejected by the explore app. Sometimes I am lucky an get it paired after 5 tries, but other tim eit takes some 15 and more codes until pairing complete