ZTE MF286D can't get connection over LTE

[ImNewAtThis]

tell me what im doing wrong:
im sending 2 delta files (from imageB03naB06) over winscp to /tmp
then im cd /tmp then

adb push /tmp/delta.package /cache/
adb push /tmp/delta.signature /cache/

then picocom /dev/ttyUSB1 (or USB2 i tried both of them)
then the commands

at+fotactr=0
at+fotactr=1
at+fotactr=5
at+fotactr=8 #it gives out 8,-1 but you said somewhere its ok
at+fotactr=2
+FOTACTR: 2,0

OK
[  997.163153] usb 2-1: USB disconnect, device number 2
[  997.163896] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[  997.167451] option 2-1:1.2: device disconnected
[  997.175438] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[  997.179700] option 2-1:1.3: device disconnected
[  997.188362] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[  997.192074] option 2-1:1.4: device disconnected
[  997.200375] qmi_wwan 2-1:1.5 wwan0: unregister 'qmi_wwan' usb-xhci-hcd.0.auto-1, WWAN/QMI device

FATAL: read zero bytes from port
term_exitfunc: reset failed for dev UNKNOWN: Not a tty
root@OpenWrt:/# [ 1014.926435] usb 2-1: new SuperSpeed USB device number 3 using xhci-hcd
[ 1015.113956] option 2-1:1.2: GSM modem (1-port) converter detected
[ 1015.114433] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB0
[ 1015.119797] option 2-1:1.3: GSM modem (1-port) converter detected
[ 1015.126212] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB1
[ 1015.132624] option 2-1:1.4: GSM modem (1-port) converter detected
[ 1015.139094] usb 2-1: GSM modem (1-port) converter now attached to ttyUSB2
[ 1015.176196] qmi_wwan 2-1:1.5: cdc-wdm0: USB WDM device
[ 1015.177649] qmi_wwan 2-1:1.5 wwan0: register 'qmi_wwan' at usb-xhci-hcd.0.auto-1, WWAN/QMI device, 22:22:33:22:22:11

then i wait that 5 minutes and do reboot by command to update the ati but it don't updated itself it still show B03...

[AndrewZ]

This is not what this topic is about.
You need to be on TELIAMF modem firmware already in order to use incremental updates for that base version. You will need to use a ZTE framework to flash it, but that has nothing to do with OpenWrt.
I suggest you to seek help with update at https://eko.one.pl/forum/viewtopic.php?id=21847

[ImNewAtThis]

I have solution - all you need to do if u have the same modem fw as I is to revert back to offical router firmware (replace mtd9) and do play to nordic + openwrt framework, then update openwrt install required packages check if u have telia modem firmware and the update it to B12 veirsion one by one as it is writen in the instruction. Good luck and don't give up!