This project illustrates how to work with device-based override.
It defines an RPC to set the factory confguration, e.g.:
$ mos call Test.SetFactoryConfig1 '{"foo": 234, "bar": "fff"}'
To add a part that zeroes out the config partition on initial flashing:
$ mos create-fw-bundle -i build/fw.zip -o build/fw_conf.zip conf:ptn=conf,fill=0xff,size=0x2000,encrypt=true
To embed a static config file conf1.json into firmware image (for debugging purposes, also not the explicit NUL termination of the file):
$ printf '\x00' >> conf1.json
$ mos create-fw-bundle -i build/fw.zip -o build/fw_conf.zip conf1:ptn=conf,src=conf1.json,encrypt=true
encrypt=true is needed if flash encryption is enabled and is ignored otherwise.
To examine raw device contents:
$ mos call Dev.Read '{"name": "conf", "offset": 0, "len": 128}' | jq -r .data | base64 -d | hexdump -C
00000000 7b 22 66 61 63 74 6f 72 79 22 3a 20 7b 22 66 6f |{"factory": {"fo|
00000010 6f 22 3a 32 33 34 2c 22 62 61 72 22 3a 22 66 66 |o":234,"bar":"ff|
00000020 66 22 7d 7d 00 00 00 00 00 00 00 00 00 00 00 00 |f"}}............|
00000030 8a e9 53 7d b0 a1 40 ab a7 50 8f ad ff ac 11 2c |..S}..@..P.....,|
00000040 5d 68 16 a4 e8 2e ce 2a 54 86 26 26 e3 9b de cb |]h.....*T.&&....|
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