I understand that the only supported method to upgrade the modem firmware from one major version to another (e.g. 1.1.x to 1.2.x) is via JTAG. As an educated guess, I would think this is due to the large size of the modem images, since the HEX files are ~5MB.
However, for product designs which have a sufficiently large file system available (e.g. SD card on SPI bus), would it be feasible to support a major version modem upgrade from there?
We have a growing number of units in the field, and some of our customers have specifically been asking for GPS improvements which it looks like the 1.2.0 release from today would help with. In our current situation, our only options to get those customers a device with modem firmware 1.2.0 is to exchange units with them, or send out a service technician with a JTAG programmer, neither of which are desirable in our situation. But if we could just send them files to put on an SD card and instructions on how to walk through and validate an upgrade, that would be manageable.
I would expect there might be a risk to this, since if it fails the upgrade, the unit could be left with a modem processor without a functional firmware image. I don't know the interconnects and controls provided between the two processors and whether there would be a method for the application processor to recover a modem processor with a broken firmware image.
I also assume that, if this feature is possible, it would have to be provided as a library in the NCS or NRFX, and would require some time to develop and test.
In the end, I'm mostly asking whether such a feature could be possible, and to request it be added to the Nordic team's backlog if so.
