MMS can clog up the phone (not receiving SMS anymore)
We have a case where people are able to send but not receive SMS. It turns out that the modem queue is full of messages with only binary/hexadecimal content, rather than being readable SMS. (I suppose they are MMS)
By clearing that queue, receiving SMS worked again:
- The person put the SIM card in their old phone to get the messages.
- View the message list
mmcli --modem 0 --messaging-list-sms - Inspect a message's content (here SMS#0) with
mmcli --modem 0 --sms 0 - Then deleted everything that appeared using
mmcli --modem 0 --messaging-delete-sms=## - I then needed to reset the modem with
mmcli --modem -r, and I have been getting messages again.
One issue is that chatty does not touch binary messages and does not consume them, so they seem to pile up in the incoming queue, clogging it. How to handle MMS in chatty/librem is being discussed here: https://source.puri.sm/Librem5/chatty/-/issues/30
So while this is an upstream issue mostly, it is not good that it is possible to DOS a person's phone by sending a few MMS, requiring a regular cleaning session. At the very least we should warn users if these messages pile up, so they can clean them out manually.
Workaround
CLI application to receive MMS: https://git.sr.ht/~amindfv/janky-mms