Bangle.js App Loader returns "Upload failed, Unexpected response"

second restart call is not needed, did you disconnect from webide? the example by gordon actually does NRF.disconnect as a first thing, if pasted on same line as whole block it will run it all before console is closed, also maybe remove comments just in case even if it should work.

I suggest to first run E.reboot() to get it to clean state, then paste

NRF.disconnect();NRF.restart(function(){
poke32(0x4001e504,2);while(!peek32(0x4001e400));
poke32(0x4001e514,1);while(!peek32(0x4001e400));
poke32(0x4001e504,1);while(!peek32(0x4001e400));
poke32(0x10001014,0x7A000);while(!peek32(0x4001e400)); 
poke32(0x10001018,0x7E000);while(!peek32(0x4001e400));
poke32(0x1000120c,0xfffffffe);while(!peek32(0x4001e400));
poke32(0x4001e504, 0);while(!peek32(0x4001e400));
});

via ctrl+v and run as single block.

oh, but just noticed - in your code you are setting reset pin again! remove those two poke32(0x10001200/4,21) lines, maybe that is the problem :-) And also you are not erasing it. You pasted wrong code, not the one I mentioned in previous post.