Using the most recent version from this repos master branch:
$ adb-sync ü /sdcard/
Traceback (most recent call last):
File "/Users/jonas/.bin/adb-sync", line 774, in <module>
main(*sys.argv)
File "/Users/jonas/.bin/adb-sync", line 695, in main
localpatterns = [x.encode(args_encoding) for x in args.source]
UnicodeDecodeError: 'ascii' codec can't decode byte 0xc3 in position 0: ordinal not in range(128)
Using the most recent version from this repos master branch: