Jakieś konkrety napisałem 
Log poniżej, najpierw w chwilę po wywaleniu się łącza:
Sat Jan 30 16:40:00 2016 cron.info crond[2038]: USER root pid 11585 cmd /bin/tester.sh
Sat Jan 30 16:40:26 2016 daemon.info hostapd: wlan0: STA 00:18:de:08:1a:d2 WPA: group key handshake completed (RSN)
Sat Jan 30 16:40:26 2016 daemon.info hostapd: wlan0: STA 74:e2:8c:c3:33:40 WPA: group key handshake completed (RSN)
Sat Jan 30 16:40:26 2016 daemon.info hostapd: wlan0: STA 00:90:4c:c5:12:38 WPA: group key handshake completed (RSN)
Sat Jan 30 16:40:30 2016 daemon.notice netifd: wan (2540): Received SIGTERM
Sat Jan 30 16:40:30 2016 daemon.notice netifd: Interface 'wan' is now down
Sat Jan 30 16:40:30 2016 daemon.notice netifd: Interface 'wan' is disabled
Sat Jan 30 16:40:30 2016 daemon.notice netifd: Interface 'wan' is enabled
Sat Jan 30 16:40:30 2016 daemon.notice netifd: Interface 'wan' is setting up now
Sat Jan 30 16:40:31 2016 daemon.notice netifd: wan (11647): udhcpc (v1.23.2) started
Sat Jan 30 16:40:31 2016 daemon.notice netifd: wan (11647): Sending discover...
Sat Jan 30 16:40:34 2016 daemon.notice netifd: wan (11647): Sending discover...
Sat Jan 30 16:40:37 2016 daemon.notice netifd: wan (11647): Sending discover...
Teraz log po ręcznym wymuszeniu ponownego połączenia:
Sat Jan 30 16:44:03 2016 daemon.notice netifd: LTE (11723): Stopping network
Sat Jan 30 16:44:03 2016 daemon.notice netifd: LTE_4 (2845): Received SIGTERM
Sat Jan 30 16:44:03 2016 daemon.notice netifd: Interface 'LTE_4' is now down
Sat Jan 30 16:44:03 2016 daemon.notice netifd: Interface 'LTE_4' has link connectivity loss
Sat Jan 30 16:44:03 2016 daemon.warn dnsmasq[2689]: no servers found in /tmp/resolv.conf.auto, will retry
Sat Jan 30 16:44:03 2016 daemon.notice netifd: Interface 'LTE_6' is now down
Sat Jan 30 16:44:03 2016 daemon.notice netifd: Interface 'LTE_6' is disabled
Sat Jan 30 16:44:03 2016 daemon.notice netifd: Interface 'LTE_6' has link connectivity loss
Sat Jan 30 16:44:05 2016 daemon.notice netifd: LTE (11723): sending -> AT^NDISDUP=1,0
Sat Jan 30 16:44:05 2016 daemon.notice netifd: LTE (11723): Command failed: Permission denied
Sat Jan 30 16:44:05 2016 daemon.notice netifd: Interface 'LTE' is now down
Sat Jan 30 16:44:05 2016 daemon.notice netifd: Interface 'LTE' is setting up now
Sat Jan 30 16:44:07 2016 daemon.notice netifd: LTE (11786): sending -> AT
Sat Jan 30 16:44:08 2016 daemon.notice netifd: LTE (11786): sending -> ATZ
Sat Jan 30 16:44:09 2016 daemon.notice netifd: LTE (11786): sending -> ATQ0
Sat Jan 30 16:44:09 2016 daemon.notice netifd: LTE (11786): sending -> ATV1
Sat Jan 30 16:44:10 2016 daemon.notice netifd: LTE (11786): sending -> ATE1
Sat Jan 30 16:44:11 2016 daemon.notice netifd: LTE (11786): sending -> ATS0=0
Sat Jan 30 16:44:11 2016 daemon.notice netifd: LTE (11786): sending -> AT^SYSCFGEX="00",3fffffff,2,4,7fffffffffffffff,,
Sat Jan 30 16:44:13 2016 daemon.notice netifd: LTE (11786): sending -> AT^NDISDUP=1,1,"internet","root","---------"
Sat Jan 30 16:44:14 2016 daemon.notice netifd: LTE (11786): Connected, starting DHCP
Sat Jan 30 16:44:14 2016 kern.err kernel: [12285.690000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
Sat Jan 30 16:44:14 2016 kern.err kernel: [12285.700000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
Sat Jan 30 16:44:14 2016 kern.err kernel: [12285.710000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
Sat Jan 30 16:44:14 2016 kern.err kernel: [12285.720000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Interface 'LTE' is now up
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Network device 'wwan0' link is up
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Network alias 'wwan0' link is up
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Interface 'LTE_4' is enabled
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Interface 'LTE_4' has link connectivity
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Interface 'LTE_4' is setting up now
Sat Jan 30 16:44:14 2016 daemon.notice netifd: LTE (11786): Command failed: Unknown error
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Interface 'LTE_6' is enabled
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Interface 'LTE_6' has link connectivity
Sat Jan 30 16:44:14 2016 daemon.notice netifd: Interface 'LTE_6' is setting up now
Sat Jan 30 16:44:14 2016 daemon.notice netifd: LTE (11786): Command failed: Unknown error
Sat Jan 30 16:44:14 2016 daemon.notice netifd: LTE_4 (11849): udhcpc (v1.23.2) started
Sat Jan 30 16:44:14 2016 daemon.notice netifd: LTE_4 (11849): Sending discover...
Sat Jan 30 16:44:14 2016 user.notice firewall: Reloading firewall due to ifup of LTE (wwan0)
Sat Jan 30 16:44:17 2016 daemon.notice netifd: LTE_4 (11849): Sending discover...
i kernel:
[12285.690000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
[12285.700000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
[12285.710000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
[12285.720000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
a tak wygląda log od modemu po restarcie, gdy łącze działa normalnie:
Sat Jan 30 13:19:07 2016 daemon.notice netifd: LTE (2409): sending -> AT
Sat Jan 30 13:19:08 2016 daemon.info procd: - init complete -
Sat Jan 30 13:19:08 2016 daemon.notice netifd: LTE (2409): sending -> ATZ
Sat Jan 30 13:19:08 2016 daemon.notice netifd: wan (2548): Sending discover...
Sat Jan 30 13:19:09 2016 daemon.notice netifd: LTE (2409): sending -> ATQ0
Sat Jan 30 13:19:09 2016 daemon.notice netifd: LTE (2409): sending -> ATV1
Sat Jan 30 13:19:10 2016 daemon.notice netifd: LTE (2409): sending -> ATE1
Sat Jan 30 13:19:11 2016 daemon.notice netifd: LTE (2409): sending -> ATS0=0
Sat Jan 30 13:19:11 2016 daemon.notice netifd: wan (2548): Sending discover...
Sat Jan 30 13:19:11 2016 daemon.notice netifd: LTE (2409): sending -> AT^SYSCFGEX="00",3fffffff,2,4,7fffffffffffffff,,
Sat Jan 30 13:19:13 2016 daemon.notice netifd: LTE (2409): sending -> AT^NDISDUP=1,1,"internet","root","----------"
Sat Jan 30 13:19:14 2016 daemon.notice netifd: LTE (2409): Connected, starting DHCP
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Interface 'LTE' is now up
Sat Jan 30 13:19:14 2016 kern.err kernel: [ 58.250000] huawei_cdc_ncm 1-1.2.5.4:1.2 wwan0: kevent 12 may have been dropped
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Network device 'wwan0' link is up
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Network alias 'wwan0' link is up
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Interface 'LTE_4' is enabled
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Interface 'LTE_4' has link connectivity
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Interface 'LTE_4' is setting up now
Sat Jan 30 13:19:14 2016 daemon.notice netifd: LTE (2409): Command failed: Unknown error
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Interface 'LTE_6' is enabled
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Interface 'LTE_6' has link connectivity
Sat Jan 30 13:19:14 2016 daemon.notice netifd: Interface 'LTE_6' is setting up now
Sat Jan 30 13:19:14 2016 daemon.notice netifd: LTE (2409): Command failed: Unknown error
Sat Jan 30 13:19:14 2016 daemon.notice netifd: LTE_4 (2853): udhcpc (v1.23.2) started
Sat Jan 30 13:19:15 2016 daemon.notice netifd: LTE_4 (2853): Sending discover...
Sat Jan 30 13:19:15 2016 daemon.notice netifd: LTE_4 (2853): Sending select for 46.113.175.190...
Sat Jan 30 13:19:15 2016 daemon.notice netifd: LTE_4 (2853): Lease of 46.113.175.190 obtained, lease time 518400
Sat Jan 30 13:19:15 2016 daemon.notice netifd: Interface 'LTE_4' is now up
Sat Jan 30 13:19:15 2016 daemon.info dnsmasq[2700]: reading /tmp/resolv.conf.auto
Sat Jan 30 13:19:15 2016 daemon.info dnsmasq[2700]: using local addresses only for domain lan
Sat Jan 30 13:19:15 2016 daemon.info dnsmasq[2700]: using nameserver 89.108.195.21#53
Sat Jan 30 13:19:15 2016 daemon.info dnsmasq[2700]: using nameserver 89.108.202.21#53
Sat Jan 30 13:19:15 2016 user.notice firewall: Reloading firewall due to ifup of LTE (wwan0)