The emoji of the flag of R.O.China will not be shown if either of the following is true:
- The device (Mac or iOS device) is bought from mainland China, determined by hardware serial number
- The "Region" setting is set to China
The People's Republic of China doesn't allow the Republic of China flag to be displayed, so the only effective way to show the flag correctly is buying the device from other countries (or Hong Kong).
After confirming with Apple Store Genius in mainland China (P.R.C), this is completely depended on the hardware serial number.
The confirmed affected products include
If the hardware serial number is registered in P.R.C (normally all devices purchased from mainland China), the flag won't be shown no matter how you change the Region in Setting.
However, devices purchased from all the other regions, including Hong Kong and Macau, the flag can be rendered if the Region in Setting is not set to China, but the flag will be a tofu if you set to China.
I've contacted a friend live in mainland China, and did an experiment, the result is the same (all depends on hardware S/N), for our safety, some personal information has been covered.
Screenshots are removed since my friend has some concerns.
A comment is asking about how to tell the country/region of hardware S/N.
I'm not sure how mac S/N work for this situation cause I couldn't find related information on my MBP (10.13.6 beta), however, there is a common way for iOS products.
Check About in Setting -> General, if the ending characters are
CH/A in the
Model section, then its S/N is highly possible registered in P.R.C.
- TW (R.O.C) ->
- USA ->
Here is the possible list from wiki https://www.theiphonewiki.com/wiki/Model_Regions