Cydia is terrible at updating itself and it’s dependencies when you let it get outdated or use older jailbreak packages without first updating the cydia.pkg within. So if you happen to be say Jailbreaking you iPod Touch 4th Generation on iOS 6.1.6 and you get this error (Type ‘reboot’ is not known on line 1 in source list /ect/apt/sources.list.d/saurik.list) while upgrading the essentials, fear not! It’s a Simple Fix!
Just connect your device to your computer and use iFunBox then select “Raw File System” to browse to “/ect/apt/sources.list.d/saurik.list”, locate the “saurik.list” file and open the file in any text editor.
Now DELETE the line that says “reboot”, save the file. Launch Cydia and select “Sources” from the bottom menu. Then tap “Refresh” in the top left.