You won't be able to get it back to CID49, if you flash it with CID50. And there are very few patches available for CID50. And R4EA031 is better and more popular cuz we will find lot of patches available for it. And its bit stable than previous version R4DB005. And just to add here that firmware R4EA031 has different FS version "R4ED001".
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rattlesnake