One of the most popular practices amongst software developers is to leave ‘backdoors’ within the code, which essentially allow anyone with knowledge to get into the system at a much deeper level than you’d expect from an end-user. These backdoors aren’t always with a malicious intent; most of the time, they allow the OEM or programmer to get into the system for troubleshooting when other, usual modes of access have been blocked. They can be quite friendly and helpful if you know what you’re doing.Smartphones have a good share of these as well, where they’re generally known as secret codes. Most of the time, these numeric/symbolic sequences allow you to access hidden menus, diagnostic tests, areas that could change some of the most basic parameters of your device and whatnot. These secret codes, in fact, have not been exclusive to smartphones, but have long been a part of the dumb-phones and then the feature-phones before most major OEMs joined the smartphone bandwagon. For those devices that run Android, certain codes are shared across the board, and hence, can be used on a variety of devices.
