Yes, your firmware was extracted successfully. You can use it as a backup, if you fuck your firmware up you can always flash this one back to restore your player to full functionality.
And no, SigmaTel firmwares can't be themed yet. Maybe
Dancemammal will make his firmware editor support SigmaTel devices too, but right now he's busy coding a Rockchip firmware extractor so i don't know if he'll do it.
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For my dreams i hold my life...
I miss my Meizu M6SL... Currently rocking a Sony Ericsson w595 on Samsung in-ear phones. Does fine, but it's not a chipod...