Replicant

h1. QMI-RIL

This page covers development efforts to create a "Radio Interface Layer":https://en.wikipedia.org/wiki/Radio_Interface_Layer (RIL) for modems that use the Qualcomm MSM Interface (QMI) protocol. The work is currently carried out for the Galaxy S 3 4G (I9305) which has a Qualcomm MDM9615 modem. The Galaxy Note 2 4G (t0lte) uses the same modem and this device could be supported as well in Replicant when the QMI-RIL is ready. We will hopefully identify further candidates that have an isolated modem using the QMI protocol and for which Replicant support could be added. Among the non-Android devices, the iPhone 5  is one that "uses the MDM9615 modem":https://www.theiphonewiki.com/wiki/MDM9615 as well.

h2. Modem boot

When the MDM9615 modem is activated, it first boots into a download mode. There, firmware, bootloaders and EFS files are uploaded to the modem via a serial interface. The used protocol is called SAHARA and it is a proprietary protocol developed by Qualcomm. The protocol covers various functionalities. We will likely only need to implement a very small subset that is responsible for transferring firmware and other files to the modem and possibly synchronising changes to EFS files with the filesystem.

Qualcomm provides the proprietary tool kickstart for uploading the files to the modem. It is run by the daemon qcks. The options qcks supplies to the kickstart show which files need to be transferred:

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/system/bin/ks -v  -w /data/cp_log/ -p /dev/ttyUSB0 -f 0 -r 21 -s 2:/firmware/image/amss.mbn -s 6:/firmware/image/apps.mbn -s 8:/firmware/image/dsp1.mbn -s 11:/firmware/image/osbl.mbn -s 12:/firmware/image/dsp2.mbn -s 21:/firmware/image/sbl1.mbn -s 22:/firmware/image/sbl2.mbn -s 23:/firmware/image/rpm.mbn -s 28:/firmware/image/dsp3.mbn -s 16:/tombstones/qcks/efs1.bin -s 17:/tombstones/qcks/efs2.bin -s 20:/tombstones/qcks/efs3.bin -s 29:/tombstones/qcks/acdb.bin

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