B1W Firmware

llllllmb

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Dash Cam
Blueskysea B1W, SJCAM M10
I poked around in the B1W firmware with Ghidra and found references to various video modes and things which are not available via the app (CBR, VBR, quantizer; bitrate...). However I have no idea how to modify these settings. From my understanding they are read from a certain block of memory within the ROM file(?), however I'm unable to locate / extract / identify it with "binwalk", "file" and other tools.

Firmware downloads are provided with a 512 byte default_cfg.bin config file that set some defaults, video settings do not seem to be located in there from what I found (I have little knowledge about reverse engineering and fw hacking).

Has anyone does any mods to the B1W firmware yet? Is there a nice way to unpack it (instead of analyzing the whole 1.6MB file in Ghidra as a whole)?

The camera uses the Novatek Grain Media GM8135S CPU, I found some stuff for other cameras, references to certain files in the fw (factory.txt, yeecam_test, focusin.bin) and mods on a Mi camera but they seem to differ a lot between cameras.
 
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The camera uses the Novatek GM8135S CPU, I found some stuff for other cameras, references to certain files in the fw (factory.txt, yeecam_test, focusin.bin) and mods on a Mi camera but they seem to differ a lot between cameras.
the usual Novatek tools may not work for you, the chipset is by Grain Media, http://www.grain-media.com/html/8136S_8135S.htm they reference it as Novatek as Novatek took over Grain Media about 18 months ago http://www.grain-media.com/html/press/20170103_eng.htm so it comes under the Novatek family now, most of the info you'll find about reverse engineering will be for the Novatek chipsets
 
Yes you are right, the Novatek tools I found do not work with the firmware files.

The Mi camera I mentioned has the same GM8135S/8136 though, yet seems to use a different kind of file scheme for configs and flashing (https://github.com/Filipowicz251/mijia-1080P-hacks/wiki).

https://github.com/zzerrg/gmfwtools - I tried this tool to extract partitions from the b1w fw but but the signatures for the b1w fws are mismatching (error with exec_sz).
 
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