ASUS laptop ux410u doesn't see additional RAM

My laptop only has 8GB of RAM, which is probably soldered. So I wanted to install an additional stick for another 8GB. I saw several videos on the Internet where they also installed 16GB and 8GB and everything worked fine, but for me only 8GB is still displayed everywhere. I also tried one of 16GB from Kingston, the result was the same, it's not visible in BIOS or Windows Task Manager. In CPU-Z and AIDA64 the new 16GB stick is displayed, the frequency and volume correspond to the declared ones, but only 8GB is used. I tried updating the BIOS, installed Linux (you never know, it will help), but

Question by Levitifox on Super User, licensed CC BY-SA. We show a short excerpt and link to the original thread as credit.