bootloader is not working

hi,
recently after uploading a sketch to my arduino uno i got the following message:

"avrdude: verification error, first mismatch at byte 0x0000
0xff != 0x0c
avrdude: verification error; content mismatch
avrdude: verification error; content mismatch"

after some research i figured i needed to connect another arduino to it to reset to bootloader. i followed the instruction from here: https://www.arduino.cc/en/tutorial/arduinoISP

and got the following message from the second arduino after pressing the "burn bootloader":

"avrdude: verification error, first mismatch at byte 0x7e00
0xff != 0x11
avrdude: verification error; content mismatch
Error while burning bootloader."

i checked the wiring many times and all other configurations i needed for this.

pls help
thanks

TOPIC MOVED to STK BOOTLOADER

Please READ THIS for future reference thanks.

Bob.

Have you tried to reload the BOOT-loader using the IPSC interface ?

KRIS

Many reasons can be. Post the picture of your wiring setup and full log include the command.

@snestrup2016 He wrote that he had already tried Arduino as ISP.