Originally Posted by Mastamike
Did you have the possibility to check if the mi 9 can correctly aggregate b3/b7 and b3/b20?
I'm from Belgium and the 3 operators use mostly b3/b20 and sometimes b3/b7. It should be very similar in Netherlands.
I still have to wait another 100+ hour for my unlock, so I cannot show you the details (need root), but I'm pretty sure the 3ca is working, as I got my carrier's full 225 Mbps speed at some locations (as in: real-life performance) including the 4G+ and VoLTE icons too.
EDIT: 225Mbps could still be 2CA technically, so I dug a bit deeper into the (official Dutch) specs:
4G: LTE FDD: B1 / 2/3/4/5/7/8/12/20/28; LTE TDD: B38 / B39 / B40
3G: WCDMA: B1 / B2 / B4 / B5 / B8; TDSCDMA: B34 / B39; CDMA EVDO BC0
2G: GSM: B2 / B3 / B5 / B8; CDMA 1X: BC0
And 4x4 MIMO | HPUE | HO RxD
Please also note that I do still need to do the *#*#4636#*#* trick to set the modem to LTE/WCDMA on each
reboot to prevent Cell Standby drain and reception issues on my official global ROM (10.2.9.0); can't wait for the unlock waiting-period to be over ...
PS: I believe the Cell Drain to be caused (at least partially) by not only searching for those unused frequencies in Europe by default, but also when it actually finds a working legacy 2G or 3G frequency, it desperately tries to keep that connection alive in standby-/sleep-modus instead of using higher speed 3G and 4G frequencies to try & save battery, but because legacy frequency towers are very sparse and far between in my country (they're even talking about killing 3G off in a few years already), it actually drains the battery way more than simply using that stellar 4G signal from the brandnew tower just a few hundred meters away.