Update rsync in high sierra

I finally figured out that apart from updating rsync, I also had to switch the order in which I specified the character sets: I thought you were supposed to specify the character set in the order of transformation; but it seems as that is not the correct syntax. Rather, one should always use --iconv=utf-8-mac,utf-8 when initialising the rsync from the mac, and always use --iconv=utf-8,utf-8-mac when initialising the rsync from the linux machine, no matter if I want to sync files from the mac or linux machine.

Then @Mark's solution works like magic!

Try System Preferences -> Startup Disk -> macOS. I updated Sierra on my MBP (late 2016) and was unable to boot into Boot Camp. Fixed over the phone with Apple, but then I was unable to boot into macOS. They fixed that at the Apple store today using the above commands.

If you want to boot into Windows directly, just hold down the "option" key while you press power on button. This saves you from having to log in to macOS and then restarting while holding down the option key.