Comma four physical SIM card installation

[nelsonjchen]

• It does not void your warranty (unless you're really reckless)
• It does require opening the C4
• The guide might want to refer elsewhere for software matters like setting APN and etc.

[zikeji]

We have this post and guide for physical installation: https://discord.com/channels/469524606043160576/1436852432503046294/1458782571155558491

You should just be able to install and then set the APN in the interface, however:

The caveat is if you are installing a psim on the T-Mobile network (a MVNO qualifies as well, so if your MVNO, such as Project Fi, uses T-Mobile) you'll need to override the esim and set DNS:

Alright, since this nearly drove me insane in case anyone needs it - some nuances to using an psim.

---

If your physical sim is T-Mobile (or an MVNO, so may just want to do this to be safe) you'll need to prioritize it over the esim.

Ref: https://discord.com/channels/469524606043160576/1436852432503046294/1456483367179518105

nmcli connection modify lte connection.autoconnect-priority 999

---

If you still aren't getting network connectivity, it may just not be getting DNS.

Ref: https://discord.com/channels/469524606043160576/1436852432503046294/1464103347966578872

You can set it manually like so:

nmcli connection modify "lte" ipv4.dns "8.8.8.8 1.1.1.1"
nmcli connection modify "lte" ipv4.ignore-auto-dns yes
nmcli connection up "lte"

Following the above outlined steps I was able to successfully get online on my own physical sim card. Collating these notes here since the whole digging-through-Discord approach and finding them was nothing short of a miracle.

[yuzisee]

Is it true that at some point during https://github.com/commaai/openpilot/commits/52e25ebe4e5e1786ce1310a35cb4e071987602d5/system/hardware/tici/modem.py openpilot stopped using ModemManager altogether for cellular

https://discord.com/channels/469524606043160576/1436852432503046294/1516138416364978356

and so T-Mobile pSIM users will need e.g.

resolvectl dns ppp0 1.1.1.1 8.8.8.8

if running the current 0.11.1 release, at least until commaai/openpilot#38213 makes it into the next release (probably 0.11.2?)