Another baseband question: what does it do?

[svenn]

All this talk about preserving basebands and trying to downgrade, but I am wondering what it actually does?

I know only certain versions are unlockable, but are you losing anything by not updating? If you keep an old version, is it possible to not have service in some areas because you cannot communicate with a new tower?
Are you missing out on improved voice quality with new updates?
Can updates provide any change in data speeds?
Or is it simply a way for carriers to try and lock you in with their service? It has to do something else, too, right?

Just curious.

 

[Krevnik]

The baseband firmware does run the cell modem (and anything else integrated into it, like GPS on the Verizon iPhone model, for example).

Since it's tied to a specific chip, you usually won't see new features or enhancements in updates. You will see bugfixes and maybe performance improvements through optimization (not large leaps). It does handle SIM locking though, which is why patching it can SIM unlock a phone. So you will miss out on some small things which you may or may not even notice (most likely won't).

The reason for watching upgrades is that the way stuff like ultrasn0w works is by exploiting security holes in the baseband in order to apply the patch. Once these exploits become known, Apple will then get them fixed in the next update usually, and so the writers of these baseband unlocks have to find a new security hole.

 

[svenn]

Thanks for the info. You must have covered it sufficiently, or no one else knows the answer. Let's assume the first

 

[svenn]

Really? No other replies?

 

[ulbador]

What else do you expect? I think the first answer pretty much covers it.

I guess it also allows unicorns to exist. But that should be it.

 

[IBradMac]

I was thinking about this very thing the other day. All the talk about 4.3 and some reports of "better service" got me wondering... I'd like to know more.

 

[Applejuiced]

I doubt it does any more than patch exploits.
Maybe with the CDMA iphone since its brand new and issues on the first device might come up yes but on the GSM model there isnt much difference as The Dev Team pointed out.

 

[synagence]

I doubt it does any more than patch exploits.
Maybe with the CDMA iphone since its brand new and issues on the first device might come up yes but on the GSM model there isnt much difference as The Dev Team pointed out.

Not necessarily .... i think Apple is still developing and understanding global networks more and more ... its a highly specialised and complex area of the OS and the overall signal retention / cell tower handoff process is evolving

 

[Applejuiced]

Not necessarily .... i think Apple is still developing and understanding global networks more and more ... its a highly specialised and complex area of the OS and the overall signal retention / cell tower handoff process is evolving

True.
But more so on the newer CDMA iPhone.
The gsm iPhone has 4 years of experience and work behind it.
But probably there's still room for improvements.

 

[Krevnik]

True.
But more so on the newer CDMA iPhone.
The gsm iPhone has 4 years of experience and work behind it.
But probably there's still room for improvements.

This isn't entirely accurate, Apple's used 3 different baseband chipsets in 4 models (2G, 3G, and the different 3G chipset in the 4). They have 3 different sets of firmware. And it is surprising if Apple has 100% full access to the firmware source, since that is usually provided by the chipset OEM.

The sort of bugs that crop up in these firmwares are usually specific to the firmware, and not something you can take from baseband to baseband. I might have a bug with how I push data into a register on this one chip that doesn't apply to the other chip.

The CDMA/GSM chip in the Verizon iPhone is the same deal, since it is a different Qualcomm chipset that is different from the other 4. So it has its own firmware that will need to be maintained, and so fresh bugs will be found with it (such as the GSM issue).

 

[bripab007]

I think maybe 50% of the baseband firmware engineers' time is spent patching security holes (not necessarily related to unlockability, but just general cellular technology security to prevent snooping, hacking OTA, etc.) and and the other half the time is spent enhancing the modem's features and capabilities to extend battery life, improve speed or call quality, etc.

Here's a good example of a baseband update that is supposed to help with network congestion and battery life of the phone: http://www.engadget.com/2010/11/30/ios-4-2-supports-new-tech-to-reduce-network-congestion-nokia-si//