Qin F21 Pro Rom -

There is a notorious issue with the Chinese built-in SMS app. If you send an English text, it might trigger a "Spam detected" block because the Chinese firewall believes English messages are promotional. The only fix is to replace the stock SMS app with Google Messages or QKSMS via ADB.

Typical for MediaTek (MT6761/Helio A22) devices: qin f21 pro rom