iPhone 4S recovery error 29
I just fixed the error by changing the battery. Before a week I replaced my battery, but it was a Chinese battery from ebay. This was the reason for the error. Today I just changed the battery - inserted the original battery and BOOM. The iOS 9.1 was installed on my iPhone. You should try this will work 100%.

Source: http://www.unlockboot.com/2015/10/how-to-fix-itunes-error-29-iphone-4s-5.html