I used quectel-CM v1.5.9 with busybox udhcpc v1.30.1 trying to get assess to LTE network but failed.
According to log, after it obtained an IP, next step is querying data call, but always failed here.
Following is the full log
root@imx6ul-var-dart:~# /tmp/quectel-CM -s internet -4
[06-10_10:03:06:089] Quectel_QConnectManager_Linux_V1.5.9
[06-10_10:03:06:093] Find /sys/bus/usb/devices/2-1 idVendor=0x2c7c idProduct=0x125, bus=0x002, dev=0x004
[06-10_10:03:06:094] Auto find qmichannel = /dev/cdc-wdm0
[06-10_10:03:06:094] Auto find usbnet_adapter = wwan0
[06-10_10:03:06:094] netcard driver = qmi_wwan, driver version = 22-Aug-2005
[06-10_10:03:06:095] Modem works in QMI mode
[06-10_10:03:06:126] /proc/1426/fd/7 -> /dev/cdc-wdm0
[06-10_10:03:06:127] /proc/1426/exe -> /usr/libexec/qmi-proxy
[06-10_10:03:08:133] cdc_wdm_fd = 7
[06-10_10:03:08:208] Get clientWDS = 17
[06-10_10:03:08:241] Get clientDMS = 2
[06-10_10:03:08:273] Get clientNAS = 2
[06-10_10:03:08:304] Get clientUIM = 2
[06-10_10:03:08:336] Get clientWDA = 1
[06-10_10:03:08:368] requestBaseBandVersion EG25GGBR07A08M2G
[06-10_10:03:08:496] requestGetSIMStatus SIMStatus: SIM_READY
[06-10_10:03:08:497] requestSetProfile[1] internet///0
[06-10_10:03:08:560] requestGetProfile[1] internet///0
[06-10_10:03:08:592] requestRegistrationState2 MCC: 466, MNC: 89, PS: Attached, DataCap: LTE
[06-10_10:03:08:624] requestQueryDataCall IPv4ConnectionStatus: DISCONNECTED
[06-10_10:03:08:625] ifconfig wwan0 down
[06-10_10:03:08:659] ifconfig wwan0 0.0.0.0
[06-10_10:03:08:720] requestSetupDataCall WdsConnectionIPv4Handle: 0x872db360
[06-10_10:03:08:848] ifconfig wwan0 up
[06-10_10:03:08:877] busybox udhcpc -f -n -q -t 5 -i wwan0
udhcpc: started, v1.30.1
udhcpc: sending discover
udhcpc: sending select for 10.150.64.12
udhcpc: lease of 10.150.64.12 obtained, lease time 7200
[06-10_10:03:54:060] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:03:54:061] requestQueryDataCall err = 110
[06-10_10:04:39:113] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:04:39:113] requestQueryDataCall err = 110
[06-10_10:05:24:192] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:05:24:193] requestGetIPAddress err = 110
[06-10_10:05:24:193] requestDeactivateDefaultPDP WdsConnectionIPv4Handle
[06-10_10:05:54:194] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:05:54:195] requestDeactivateDefaultPDP err = 110
[06-10_10:05:54:195] ifconfig wwan0 down
[06-10_10:05:54:232] ifconfig wwan0 0.0.0.0
[06-10_10:07:54:249] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:07:54:250] requestSetupDataCall err = 110
[06-10_10:07:54:250] try to requestSetupDataCall 5 second later
[06-10_10:08:24:251] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:08:24:252] requestRegistrationState2 err = 110
[06-10_10:08:54:253] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:08:54:253] requestQueryDataCall err = 110
[06-10_10:08:54:289] requestRegistrationState2 MCC: 466, MNC: 89, PS: Attached, DataCap: LTE
[06-10_10:09:24:290] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:09:24:291] requestQueryDataCall err = 110
[06-10_10:09:24:305] requestRegistrationState2 MCC: 466, MNC: 89, PS: Attached, DataCap: LTE
[06-10_10:09:24:336] requestSetupDataCall WdsConnectionIPv4Handle: 0x872db360
[06-10_10:09:54:337] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:09:54:338] requestGetIPAddress err = 110
[06-10_10:09:54:338] try to requestSetupDataCall 10 second later
[06-10_10:09:54:353] requestRegistrationState2 MCC: 466, MNC: 89, PS: Attached, DataCap: LTE
[06-10_10:10:24:354] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:10:24:355] requestQueryDataCall err = 110
[06-10_10:10:24:369] requestQueryDataCall IPv4ConnectionStatus: CONNECTED
[06-10_10:10:54:370] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:10:54:371] requestGetIPAddress err = 110
[06-10_10:10:54:371] requestDeactivateDefaultPDP WdsConnectionIPv4Handle
[06-10_10:10:54:448] requestSetupDataCall WdsConnectionIPv4Handle: 0x872db360
[06-10_10:11:24:513] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:11:24:514] requestQueryDataCall err = 110
[06-10_10:11:24:528] ifconfig wwan0 up
[06-10_10:11:24:552] busybox udhcpc -f -n -q -t 5 -i wwan0
udhcpc: started, v1.30.1
udhcpc: sending discover
udhcpc: sending select for 10.150.64.12
udhcpc: lease of 10.150.64.12 obtained, lease time 7200
[06-10_10:12:09:752] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:12:09:752] requestQueryDataCall err = 110
[06-10_10:12:54:793] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:12:54:793] requestQueryDataCall err = 110
[06-10_10:13:39:873] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:13:39:874] requestGetIPAddress err = 110
[06-10_10:13:39:874] requestDeactivateDefaultPDP WdsConnectionIPv4Handle
[06-10_10:13:39:888] ifconfig wwan0 down
[06-10_10:13:39:917] ifconfig wwan0 0.0.0.0
[06-10_10:15:39:935] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:15:39:936] requestSetupDataCall err = 110
[06-10_10:15:39:936] try to requestSetupDataCall 5 second later
[06-10_10:16:09:937] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:16:09:937] requestQueryDataCall err = 110
[06-10_10:18:09:938] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:18:09:939] requestSetupDataCall err = 110
[06-10_10:18:09:939] try to requestSetupDataCall 10 second later
[06-10_10:18:39:940] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:18:39:941] requestQueryDataCall err = 110
[06-10_10:19:09:942] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:19:09:943] requestQueryDataCall err = 110
[06-10_10:19:39:944] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:19:39:944] requestRegistrationState2 err = 110
[06-10_10:19:39:951] requestRegistrationState2 MCC: 466, MNC: 89, PS: Attached, DataCap: LTE
[06-10_10:20:09:953] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:20:09:953] requestQueryDataCall err = 110
[06-10_10:20:09:968] requestRegistrationState2 MCC: 466, MNC: 89, PS: Attached, DataCap: LTE
[06-10_10:22:09:969] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:22:09:970] requestSetupDataCall err = 110
[06-10_10:22:09:970] try to requestSetupDataCall 20 second later
[06-10_10:22:39:971] QmiThreadSendQMITimeout pthread_cond_timeout_np timeout
[06-10_10:22:39:972] requestRegistrationState2 err = 110