January 27, 2022

45 thoughts on “How we fixed error 21 in this iPhone 4

  1. hey i had the same problem, i v changed the battery and it worked but the problem is next day i got the same problem again and it even does not stay on without charger ? what you think what is my problem ?

  2. Hello! I have the same problem, my iphone4s have been disabled and when I try to restore it it says it cannot be restore, error occured 2009. Can you help me with this?

  3. I had the exact same problem with my iphone 4s after i had dropped it. What i tried did not work but i thought, nothing to lose, so i changed my battery(i had an old one) and it worked. Everything still on the phone no problems at all. 👍🏻👍🏻👍🏻

  4. hey! I´ve got the iphone 4s and have the almost same problem but the screen is turning black with grey stripes on in under 3 minutes after I have unlocked it! We are now trying to restore it but then the error 29 came up. So we changed the battery and now we got the error 21… Please help me!!!!!!!

  5. this tutorial you have written ? I am with this same problem I am Brazilian and I do not speak your language , I wanted to follow in his footsteps translating

  6. had this issue with my friends iPhone lol.. I took the battery out of an iPhone that has the battery connector broken off the logic, and now it works, after 4 errors xD.. started at 21, 11, 3194, then -1 then finally iTunes worked. This helped tho lol

  7. I have this same exact issue with my iPhone 4s, I purchased a new battery and still… I get the same exact problem.

  8. i have the exact same problem, everytime i try to restore i get error 21 and when i try to charge it keeps turning on then off again. however the litmus paper or whatever you call it in the back of the phone is partially pink. do you think it's worth replacing the battery? can error 21 be cause by water damage?

  9. I tried to update to iOS 8.1.3 on a 4S using the laptop, I've tried everything and had error (4005) its like it has gone to Defcon 4 and died.. Won't do anything..

  10. Hi, my iphone 4 get a prob with logicboard…actually it was getting bend…maybe it was crack its self…can it was repair…?

  11. I have had the same issue problem 21 while trying to restore it might be the battery while is dead and cant let you finish the job!! Replace the battery and will be okay though…… Nice video dudes

  12. hello. i have the same error. will changing the battery cause me to lose all the data and media i have saved on the phone? Or is there a way to restore the phone without losing any saved information? Thanks!

  13. It kept switching on and off after randomly turning off at 17% so now I finally I tried to restore it and it probably indicates that error 21 is an issue and so now I have to replace my battery?

  14. hi i have an iphone 4 and i cant use it. all it does is flash up with the apple logo every 5 seconds, i cant access anything iv held down everything like the power and the home button at the same time and nothing is happening please help!

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