I often read about the instability of built-in wifi in Bpi-R1, but for me (OS: last Bananian) it has been stable for over 2 years. The problem is thermal, the chip is too small and requires a large heat sink - I glued it to a copper plate with an area of about 60x70 mm (it is not rectangular due to the housing and the elements on the board - it protrudes outside the housing - I specially cut a hole)
without WiFi heatsink it hung after sending 0.6-0.7 GB at max speed (samba)
after installing the heat sink, it hangs after sending 5-5.2 GB. (Samba)
Because in normal use I do not send such data via WIFI - it only serves as an AP for several phones and 1 laptop, the 5 GB limit at max speed is imperceptible to me - during normal internet use - streaming movies, music, browsing - it never freezes.