nRF93M1 DK PPP Shell Sample: Unable to Connect to Network

[Macro Yau]

Hi Nordic Team,

I've just received my nRF93M1 DK. Similar to this issue, I am unable to get my DK connected using the PPP shell sample.

Hardware: PCA10232 v0.4.0
Modem Firmware: Upgraded from v1.4.1 to v1.5.0 via the AT command below, according to the answer in this post

AT%HTTPFOTADL="http://firmware.nrfcloud.com/93m1/mfw_nrf93m1_update_from_1.4.1_to_1.5.0.bin",100

SIM Card: Onomondo card bundled with the DK
SDK: nRF Connect SDK v3.4.99
Toolchain: nRF Connect SDK Toolchain v3.4.0

Connecting to network via AT commands using the factory default / modem bypass sample firmware works as expected:

> AT
OK
> AT+GMR
CPv017pb26.005 LIBv017pb26.005
OK
> AT+CGMR
mfw_nrf93m1_1.5.0
OK
> AT+CFUN=1
OK
> AT+COPS?
+COPS: 0,2,"45406",7
OK
> AT+CGDCONT=1,"IP","onomondo"
OK
> AT+CGDCONT?
+CGDCONT: 1,"IP","onomondo","<IP Address>",0,0
OK
> AT%PING="www.google.com"
OK
%PING: SUCC, dest: 142.251.157.119, RTT: 319 ms
%PING: SUCC, dest: 142.251.157.119, RTT: 220 ms
%PING: SUCC, dest: 142.251.157.119, RTT: 220 ms
%PING: SUCC, dest: 142.251.157.119, RTT: 220 ms
%PING: DONE
%PING: dest: 142.251.157.119, 4 packets transmitted, 4 received, 0 % packet loss
 rtt min/avg/max = 220 / 244 / 319 ms

However, I am unable to get the PPP shell sample connected to the Internet. Here are my steps to reproduce:

1. Open the PPP shell sample code from the SDK folder at nrf/samples/nrf93m1dk/ppp_shell
2. Disabled IPv6 in prj.conf (CONFIG_NET_IPV6=n)
3. Explicitly set APN in prj.conf (CONFIG_MODEM_CELLULAR_APN="onomondo"); this is needed otherwise the modem uses its default "pepper" APN causing failure to attach to LTE network
4. Build the firmware image using west build -b nrf93m1dk/nrf54l15/cpuapp
5. Flash the image to the DK using west flash --erase
6. Open the Zephyr shell in serial terminal

Zephyr shell transcript showing the failure to obtain IP address, perform further network operations, and to disable the network interface:

> device list
device list
devices:
- regulator@120000 (READY)
  DT node labels: regulators
- lfclk (READY)
  DT node labels: lfclk
- xo (READY)
  DT node labels: xo
- gpio0 (suspended, usage=0)
  DT node labels: gpio0
- gpio1 (suspended, usage=0)
  DT node labels: gpio1
- gpio2 (suspended, usage=0)
  DT node labels: gpio2
- rng (READY)
  DT node labels: rng
- uart@104000 (suspended, usage=0)
  DT node labels: uart30
- uart1 (active, usage=2)
  DT node labels: uart20
- modem_ppp_ppp_nordic_nrf93m10 (READY)
- i2c@c7000 (suspended, usage=0)
  DT node labels: i2c21
- npm1300@6b (READY)
  requires: i2c@c7000
  DT node labels: pmic_main
- regulators (READY)
  requires: npm1300@6b
- LDO1 (READY)
  requires: regulators
  DT node labels: ldo1_3v3
- BUCK2 (READY)
  requires: regulators
  DT node labels: vdd_dbgr
- BUCK1 (READY)
  requires: regulators
  DT node labels: vdd_nrf
- buttons (suspended, usage=0)
  requires: gpio0
  requires: gpio1
- temp@d7000 (READY)
  DT node labels: temp
- charger (READY)
  requires: npm1300@6b
  DT node labels: npm1300_charger
- modem_dcdc (suspended, usage=0)
  requires: gpio1
  DT node labels: modem_dcdc
- modem (off, usage=0)
  requires: gpio1
  requires: gpio2
  requires: uart@104000
  requires: modem_dcdc
  DT node labels: modem
uart:~$ > net iface
net iface
Hostname: zephyr
Default interface: 1


Interface ppp0 (0x20002a14) (PPP) [1]
==============================
Interface is down.
uart:~$ > net iface up 1
net iface up 1
EVENT: L3 [1] IPv4 mcast address add 224.0.0.1
Interface 1 is up
EVENT: L2 [1] interface admin up
[00:01:54.451,999] <inf> power_domain_gpio: modem_dcdc is now ON
[00:01:56.619,130] <inf> modem_at_user_pipe: pipe connected
[00:01:56.619,165] <inf> modem_at_user_pipe: opening pipe
[00:01:56.623,501] <inf> modem_at_user_pipe: pipe opened
EVENT: L2 [1] interface up
EVENT: L4 [1] DNS server add 172.30.8.5
EVENT: L4 [1] DNS server add 172.30.8.6
EVENT: L4 [-1] <unknown event>  (0xf050000000008000)
EVENT: L3 [1] IPv4 address add <IP Address>
EVENT: L3 [1] IPv4 address del <IP Address>
uart:~$ > net iface
net iface
Hostname: zephyr
Default interface: 1


Interface ppp0 (0x20002a14) (PPP) [1]
==============================
Link addr : 51:30:30:30:59:44:44:36
MTU       : 1500
Flags     : NO_AUTO_START,IPv4
Device    : modem_ppp_ppp_nordic_nrf93m10 (0x32a00)
Status    : oper=UP, admin=UP, carrier=ON
IPv4 unicast addresses (max 1):
        <none>
IPv4 multicast addresses (max 2):
        224.0.0.1
IPv4 gateway : 0.0.0.0
uart:~$ > net dns
net dns
DNS servers:
        172.30.8.5:53 via ppp0 (PPP)
        172.30.8.6:53 via ppp0 (PPP)
Pending queries:
uart:~$ > net dns www.google.com
net dns www.google.com
Cannot resolve 'www.google.com' (-2)
uart:~$ > net ipv4
net ipv4
IPv4 support                              : enabled
IPv4 fragmentation support                : disabled
IPv4 conflict detection support           : disabled
Path MTU Discovery (PMTU)                 : disabled
Max number of IPv4 network interfaces in the system          : 1
Max number of unicast IPv4 addresses per network interface   : 1
Max number of multicast IPv4 addresses per network interface : 2

IPv4 addresses for interface 1 (0x20002a14) (PPP)
===============================================
Unicast:

Type            State           Ref     Address

Multicast:

Joined  Ref     Address
yes     1       224.0.0.1
uart:~$ > net iface down 1
net iface down 1
EVENT: L3 [1] IPv4 mcast address del 224.0.0.1
EVENT: L3 [1] IPv4 mcast leave 224.0.0.1
EVENT: L2 [1] interface down
Cannot take interface 1 down (-11)
uart:~$

Thanks!