If you are able to access download mode, you could flash stock by ODIN.
Samsung Galaxy S3 (SGH-i747) | Android KitKat 4.4.2 CyanogenMod 11 Nightlies
Samsung Galaxy Tab 2 (SGH-i497) | Android JellyBean 4.1.2 Stock
Nexus 7 (2013) | Android KitKat 4.4.2 Stock
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