Smartphone companies often launch improved version with more RAM and storage, occasionally paired with faster chipset. However, it looks like local Chinese companies have better solution. If you like your Nexus 5X, but you would like to have more RAM, for $60 you can.
According to XDA member Cathair2906, he paid $60 to repair the Nexus 5X after bootloop issue. The good news is that the phone came back with 4 GB of RAM instead of 2 GB. The phone has been running without problems so far and he also tested it with official Android 6.0.1 and Android 7.1.1 ROMs.
"My Nexus 5x was bought last year from Hong Kong and got a bootloop issue just after the warranty so far, I know google has known this issue and there is a recall in U.S., Korean LG has offered an unlimited warranty to this bootloop issue. However, LG customer center from Hong Kong has rejected any maintenance of the CPU if outside its warranty
Thereafter, i decided to send my 5x to China for CPU fixing, as the RAM is packed with the CPU together, the guy suggested me upgrading it to 3 or 4 GB RAM. That's how the 4GB RAM 5X comes out.
I've tested the OTA works fine from 6.0.1 to 7.1.1, all functions work fine too."