B1W Firmware

llllllmb

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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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jokiin

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Too many ¯\_(ツ)_/¯
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
 
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llllllmb

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Blueskysea B1W, SJCAM M10
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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