Look for the most recent build number. Download the full ZIP file (usually 1.5GB to 2.5GB). Do not extract it into a folder yet—create a dedicated folder on your PC desktop called Motorola_Flash and extract the ZIP there.
For Motorola enthusiasts and modders, Lolinet (mirrors.lolinet.com) motorola firmware lolinet upd
A device stuck in fastboot loop with “No valid operating system” was recovered using Lolinet: Look for the most recent build number