In particular, a XDA member "Cathair2906" decided to send his Nexus 5X with Bootloop issue to China for CPU fixing and apart from fixing the Bootloop, the local company made it possible to upgrade the RAM of the Nexus 5X, at a minimal cost of $60.
For more adventurous folks, who don’t mind voiding their warranty, local companies in China will happily upgrade your RAM, all the way up to 4GB, for up to CNY 400 ($60). If you don’t want to go up to 4GB, you can upgrade to 3GB for a low price.
The Nexus 5X (4GB RAM) user reportedly updated his device from Android 6.0.1 Marshmallow to 7.1.2 Nougat without any issues. The smartphone is much faster than before, claims the Nexus 5X user.
This is likely a practice that won’t take off in your country in any real capacity, but for those that can make it to the China, and don’t mind voiding their warranty, it’s a quick and cheap option to upgrade the RAM available in your device pretty quickly.