Rockchip tools for modifying the FW are available (see posts elsewhere on this forum) - just no tools to extract them from an actual player
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While most Rockchip players have very similar features, flashing a software for a diff. Rockchip player will probably render yours non-functional due to e.g. a different display, different input controls etc. Unless you find out the real mfg. or get a matching fw from UXCell, DON'T update!
As it says on UXCell's site: "the steps are complicated and can easily render your mp4 player un-usable if you cannot find the matching firmware version"
Rockchip FW updates for "brand-name" players such as e.g. Teclast or Onda, adding new features are easily found on the respective mfg's homepages.
Cheers ...