ITunes Errors/-100 to -1

From The Apple Wiki

Error -54[edit source]

Permission error either on your computer or the device.

Error -50[edit source]

Reinstall iTunes.

Error -35[edit source]

Error when downloading songs purchased on iTunes. Also see KB TS1475.

Error -1[edit source]

Error occurs when one uses the "last ditch" method for preventing baseband updates on the iPhone 4. The baseband does not get updated using this method. Use TinyUmbrella or redsn0w to kick it out of Recovery Mode.

Also occurs in restore logs as "unable to convert ramrod 1004." Seemingly caused by a modem firmware chipset malfunction or faulty dock connector, the only fix is to either heat up the chipset or replace the dock connector.