Hi all SIFU, I got issue to my Iphone 6s, it probably get overheat while charging, the battery is flat until cannot turn on, when plug in the USB cable it show the Itunes logo, tried Recovery mode and DFU mode to flash the latest firmware, it showed Error 2009, after that i suspect is the battery issue. because it cannot charge at all and unable to boot, then i go to the shop and change the battery. after changed the battery is working fine, but still stuck at the Itune logo, then i tried to reflash it, it become Error 9..... :s tried go back the shop, the technician said is not their problem. i am quite lost here.

what i have tried.
- itunes - latest version , flash failed (Error 9)
- changed computers , flash failed (Error 9)
- tried different beta firmware. flash failed (Error 9)
- used third party flashing tools, Reiboot & 3utools, flash failed (Error 9)
- Changed the charging connector & original USB cable, flash failed (Error 9)

I have done some research, Error 9 is an unknown issue, it can be hardware, it can be software or both.

Is there anybody can recommend me any shop can provide better service?

Or should i send back to Apple workshop to repair, since the repair cost can be very high now.....

New update:

When the phone shop changed the battery, the phone still stuck at the Itunes Logo. Then the technician refused to solve the issue, and ask me go back to the Apple shop.

No refund money at all .

But if i go back Apple shop, would they knew my phone sent to the repair shop or not?