CellularModem¶

If you are new to modems, or to the hardware and software architecture used in smartphones and tablets, it's a good idea to start from the freedom-privacy-security-issues article .

Once this is done, there are more documentation on various aspects of the Cellular modem, from the protocol to implementations details.

• BackupTheEFS: The EFS is a partition that contains modem data like the IMEI. If that partition is lost or corrupted, the modem doesn't work anymore, so be sure to backup it.
• CellularModemPrivacyIssues:
  • ModemIsolationResearch: Research on how to isolate the modem
    • ExynosModemIsolation: Issue affecting devices that are not supported by Replicant anymore.
  • LocationTracking: Research on how to avoid location tracking
  • SamsungGalaxyBackdoor: A backdoor found in the nonfree Samsung implementation of the samsung-ipc protocol.
  • SIMCardDetection: Is it possible to boot the modem with a SIM card and take it away?
  • IMEI: Freedom, privacy and security issues
• ModemProtocols
  • AT
  • QMI: This modem protocol is used at least in the Galaxy S 3 4G (GT-I9305) and the Galaxy Note II 4G (GT-N7105). These devices need an implementation of the QMI protocol to add support for them in Replicant.
    • QMI-RIL: An attempt to implement the QMI protocol. The code can initialize the modem.
    • oFono-RIL also has an implementation of the QMI protocol that can be used on Replicant. This is now the route chosen by the Replicant project.
  • Samsung-ipc: This modem protocol is used in all the smartphones (and some of the tablets) supported by Replicant.
    • ModemFirmwarePartitions: Documentations about the modem firmware partitions
    • XMMBoot: Documentation of the modem boot
    • XMMUpstreaming: Work on driver architecture toward Kernel upstreams
    • SamsungIpcDissector: Work on a Wireshark dissector and information on the packets structure
    • libsamsung-ipc: The library that implements the Samsung-ipc protocol.
    • libsamsung-ril: The library that interfaces libsamsung-ipc with Android.
    • ModemDisable: Documentation on how to disable the modem. Currently applies to devices with the Samsung-ipc. This is needed because the flight mode doesn't disable the modem at all.
      • ModemDisableResearch: More in depth documentation and research on how to disable the modem on various devices and research on user interfaces for it.
    • SIMnotRecognized: A bug in libsamsung-ipc that affected Replicant 6.0, which resulted in SIM cards not being recognized.
    • XMMProtocolInterfaces: Research on the interfaces available (for AT interfaces on with usb_sel, and diagnostics, protocol tracing etc)
  • OtherModemProtocols: A list of other modem protocols and their implementations