(Disclaimer: I have no idea about the legal status of these software modifications. I’d suppose that you may do anything with your own property, but operation in public networks may be a different issue. Then again, I’m not a lawyer, so please keep this in mind. I will not provide links, just in case…)
A while ago, Siemens started providing firmware upgrades for their line of mobile phones on their web site. They also have been known to recklessly support open standards and publish information about the protocols being used, so it’s no surprise that add-on applications like s25@once have been flourishing.
The inevitable happened: people found ways to extract the firmware images from the updaters, and began experimenting. Things seem to be based around the HC08 microcontroller, which paved the way for assembly modifications.
In the meantime, people have created tools to work on pictures and texts in the firmware, and even to apply code patches creating new functionality. I’ll show some examples applied to the Siemens S55 here:
This modification provides an alternative to the network display: it shows signal strength on the 6 closest cells in range. Additionally, two other patches have been applied: the name of the current profile and the vibra status are being displayed on top of the display.
This modification is activated when the phone is in keypad locked mode. It provides a more detailed view of the base stations in range and their signal strength. Another patch activates the “official” network monitor inside the S55.
This is an example of a replacement image for the screen saver clock. Other graphics hacks include new icons for the menu graphics – one pack mimicks the SonyEricsson T610 menu, others make it look like a Linux, Windows XP or MacOS system. Similar replacements can be found for the start and shutdown screens.
I have no idea if Siemens intended or foresaw this – most likely not. Anyway, I think they should like it. As with Linksys routers on Linux, this makes for a devoted set of fans and followers, something that should not be underrated.
And – it creates an opportunity for the next series of phones: don’t just tolerate it, facilitate it! Provide documentation, tools (these guys know how to make them – why not license some of them?), or even an official API to work on modifications. Nokia may allow you to change the faceplates, but this goes far beyond the surface….