Rockbox Manual Install
Rockbox 3.15 was released on 15 Nov 2019. See the full Release Notes
We recommend using Rockbox Utility to install Rockbox, but if you insist you can do it manully.
Download the Firmware zip for your target below and unzip it to your device.
We also recommend grabbing the Fonts as well, and the Voice pack for english voice prompts. Other languages can be generated via the Rockbox Utility.
If you want to peek under the hood get the Source archive.