When I worked for a company that distributed malware (mostly desktop, but trying to break into mobile), we had relationships with a few people who would buy up android devices in bulk and then charge money to companies like ours to have our apps pre-installed. You could pay extra to have the app baked into a custom rom to make it non-removable.<p>The business model from our end is we&#x27;d find app developers who are willing to pay X amount per install (a conversion was usually tracked by the first time an end user opens the app), and then we pay Y amount per install to a shady phone re-seller to bake that app into the rom of their latest batch of phones. As long as X is sufficiently higher than Y to account for whatever our conversion rate is, we make our money back plus profits as the app developer pays us for conversions.<p>The shady re-sellers would take their phones with new roms and either sell direct to consumer or, in the case of the bigger guys, move those phones on to a big-box retailer.