REPORT: 4G ISSUES ON THE ONEPLUS6

OXYGEN OS 5.1.8 And previous versions:

Network provider have 2 networks, the main is FreeMobile the MNC is 20815,
the second network is a 1-megabit roaming contract on the Orange network to help cover the main network, MNC is 20801.

FreeMobile: 		3G/4G: MNC 20815
Orange (roaming):	2G/3G: MNC 20801

--------- AIRPLANE MODE ---------
4G (20815) re-selection when airplane mode is working when the phone was in 3G and on the same network (20815).
4G (20815) re-selection when airplane mode is not working when the phone was in 3G on the roaming network (20801).
4G (20815) re-selection when airplane mode is not working when the phone was in 2G on the roaming network (20801).

In conclusion, on the 3G (20815) airplane mode go to 4G but not with the other 3G (20801) network. It would be nice to be able to do a complete modem refresh to have a perfect reselection.

--------- AUTO NETWORK RE-SELECTION ---> 2G/3G/4G (Automatic) ---------
4G (20815) Switches correctly to the next antenna when traveling.
3G (20815) Switches correctly to the next antenna when traveling.
3G (20801) to 3G (20815) is working but take some time.
3G (20815) to 4G (20815) is not working, VERRY BAD!. Need airplane mode to reconnect to 4G (see video).
3G (20801) to 3G (20815) is working but 3G (20815) to 4G(20815) is not working. details: 3G 20801 ---> 3G 20815 about 3mins --> 4G 20815 about ∞ (never switching to 4G) VERRY BAD!, Need to airplane mode to reconnect to 4G (as seen above).

In conclusion, when on 3G (20815) the phone don't search if there is 4G available, when on 3G (20801) some times go on the good 3G (20815) network but don't search if there is 4G available.

--------- SIM AND NETWORK ---> PREFERED NETWORK TYPE ---------
When is on 2G Only (20801) and choosing 2G/3G (Automatic) The phone usualy go on 3G on the previous network (20801). This not as expected but some times go to 3G (20815), needs 0-5 mins.
When is on 2G Only (20801) and choosing 2G/3G/4G (Automatic) The phone usualy go on 3G on the previous network (20801). This not as expected but some times go to 4G (20815), needs 0-10 mins.
When is on 2G/3G (Automatic) (20801) and choosing 2G/3G/4G (Automatic) The phone stay on the same network (20801). This is bad.
When is on 2G/3G (Automatic) (20815) and choosing 2G/3G/4G (Automatic) The phone is going on 4G (20815) as expected.
When is on 2G/3G/4G (Automatic) (20815) and choosing 2G/3G (Automatic) The phone is going on 3G (20815) as expected.

So in conclusion for PREFERED NETWORK TYPE The phone looks to stay on the same MNC when the new setting is selected but some times (rare) the re-selection works. It would be nice to be able to do a complete modem refresh to have a perfect reselection.

--------- VIDEO ---------
https://www.youtube.com/watch?v=n1TcxkM9pkc
In my house upstairs, the 4G has a very good signal, then to have an automatic stall I went to the cellar to switch to 3G (20815 you can see the RP icon = Clean network) and then go upstairs to have a 4G reselection. Unfortunately it did not work, so I made a airplane mode to find the 4G. I have done this method several times, waiting the 4G for infinitely...