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use ifile on the device or ifunbox from pc or mac to get into device than do this:

Navigate to /private/etc/apt/sources.list.d

Delete the file "cydia.list"

Navigate to /var/lib/apt/lists

Delete all of the files in this folder except the one called "lock"

Navigate to /var/lib/apt/lists/partial

Delete all of the files in this folder

Navigate to /var/lib/cydia

Delete the file "metadata.plist"

Restart Cydia. You should be at the first screen you saw when you first started Cydia: What kind of user are you? Make your selection and Cydia will re-generate the default sources.
 
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