Keyboard button backtick/tilde become section symbol after replacement I have a MacBook Pro (mid-2012) with a US keyboard layout, but after a keyboard replacement I noticed my backtick/tilde key is now a section § symbol. 

After some googling, I found the Karabiner app. Yes it can remap the button but I felt that my OS (Sierra) became very slow, and I don’t want to rely on an app just for remap a single key.

Has anyone experienced this issue before? I think maybe the technician installed a different kind of keyboard (maybe a UK one) instead of US.

Note: I’ve called the service center and they will get back to me next week.
for me it was a matter of configuring the keyboard through Settings -> Keyboard and then "recognising" again "unrecognised keyboard" (i.e., my plain keyboard which was plugged in all the time) and then setting its type to US (ANSI) instead of European (ISO).