HTC, android handset maker and one of the early Android adopter, on Thursday released an interesting infographic which details the incredibly slow, painful and complex process of developing, testing, certifying and deploying Android OS firmware updates to devices in the wild.

If you use a Nexus device or a Google Edition Android smartphone you get the update almost immediately. But what about the others who have to wait for months to get that Android update? In a detailed infographic, HTC has explained the process a company has to go through to release an OS update.

The infographic shows how the update reaches to customers, from when Google releases the Platform Development Kit (PDK) to when an OEM finally releases the Over-The-Air (OTA) update. The infographic shows the process for three kinds of devices— carrier, unlocked/developer, and Google Play edition.

Android update process is very complex, where carriers, handset vendors and chipset makers, each with its own interests, often fails or even block these updates as a way of nudging customers to upgrade their hardware instead.Sometimes, Android OS updates for specific devices never arrive at all and would get lost in the complex approval and certification process which involves at least four stakeholders agreeing in order for an Android update to make it to customer devices.

Some important points from the infographic were the fact that OEMs receive PDKs of an OS update before Google officially announces the release. The process also involves a lot of testing and certifications, which though not surprising, just shows the hurdles through which an update has to go through to be cleared. In this process chipmaker also play a critical role, This often goes unnoticed, when in actuality if the company feels that the new version of the OS is not compatible with their chipset, the device ends up not getting the update.

Read the complete infographic on HTC website here.