Downloading an eSIM profile through a USB Modem without a second network device

Ironically, activating an eSIM requires an internet connection. Usually a USB modem is used in cases where another internet access isn't available. So if you need to get a new eSIM, how can you download it? Let's see how to download an eSIM profile on a USB modem without another network device. This requires having a working eSIM profile, but can help to download a new eSIM before an old eSIM expires. (A JMP eSIM is a great choice for a fallback eSIM because it doesn't expire.)

Overview

Stop ModemManager from accessing the USB modem
Use qmicli to establish a temporary network connection via the USB modem
Configure the temporary network connection
Download the eSIM profile
Restart ModemManager

Instructions

On a system with a functioning eSIM, stop the ModemManager from accessing the USB modem:
- ```
   sudo systemctl stop ModemManager
```
  The system will loose internet connectivity.
Find the USB modem's interface name:
- ```
   sudo qmicli --device=/dev/cdc-wdm0 --device-open-proxy --get-wwan-iface
```
  Keep this interface name handy and use it in place of wwp0 below.
The following steps are only necessary if the file /sys/class/net/wwp0s20u1u4u2i4/qmi/raw_ip doesn't already contain "Y"
- ```
   sudo ip link set dev wwp0 down
   sudo sh -c "echo Y > /sys/class/net/wwp0/qmi/raw_ip"
```
Bring up the interface
- ```
   sudo ip link set dev wwp0 up
```
Next we'll use qmicli to tell the modem to start a network connection using the example APN "myoldapn". Substitute it with the APN for your existing eSIM.
- ```
   sudo qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wds-start-network="ip-type=4,apn=myoldapn" --client-no-release-cid
```

Check the modem's network configuration

   sudo qmicli --device=/dev/cdc-wdm0 --device-open-proxy --wds-get-current-settings

Record the IP address, gateway and DNS address

Manually set the IP address of the interface. Substitute the IP address from above for 777.777.777.777
- ```
   sudo ip address add 777.777.777.777 dev wwp0
```
Add a default route so network traffic is routed to the USB modem's network interface
- ```
   sudo ip route add default dev wwp0
```
Test the network by pinging the gateway's IP address. Substitute the gateway address from above for 888.888.888.888
- ```
   ping -I wwp0 888.888.888.888
```
Check whether DNS is working.
- ```
   curl wiki.soprani.ca
```
  This should output "301 Moved Permanently" or some HTML.
If DNS isn't working, first test the DNS address found above. Substitute the DNS address from above (i.e. --wds-current-settings) for 999.999.999.999
- ```
   dig @999.999.999.999 wiki.soprani.ca
```
  If this works but curl wiki.soprani.ca gives a name server error, we'll need to configure DNS.
Different linux distributions use different mechanisms for DNS (e.g. resolv.conf resolvectl and systemd-resolved). If your system uses systemd-resolved,
1. edit the file /etc/systemd/resolved.conf
2. find the line starting with DNS= or #DNS=
3. remove the # and add the DNS address from above, for example
  - ```
      DNS=999.999.999.999
```
4. restart systemd-resolved
  - ```
      sudo systemctl restart systemd-resolved
```
5. verify DNS works
  - ```
      curl wiki.soprani.ca
```

Test that lpac can still access the modem via serial port

   LPAC_APDU=at AT_DEVICE=/dev/ttyUSB2 output/lpac profile list

Now return to the instructions for using lpac with a USB modem to download an eSIM profile using this network you just set up. After downloading the eSIM profile, restart ModemManager with
- ```
   sudo systemctl start ModemManager
```

eSIM Adapter/lpac via USB modem/eSIM Adapter/lpac via USB modem without internet (last edited 2024-322 04:47:27 by unn-169-150-203-10)