Beginner's little dictionary

[editheraven]

Firmware: All software in your phone (main, fs and custom-pack).
MAIN : encrypted part of your firmware. It's the part that runs java platform, media-player, manages colors of every text displayed, any image/border etc from media-player, video-player, messaging, browser etc. (somehow the OS).

FS : file-system part of your firmware. Here are stored any file used
by the operating system. Like "program files" or "documents and settings" in windows. Here are stored all files about layouts, menu, fonts, driver settings, recived sms and
so.

Custom-Pack : contains the details about localization, allowed languages, and custom text/images that can be uploaded (copyed) in FS. The Custom-pack( aka. cust) is what the phone first runs when it's sturted up. Without this first-initialisation the phone will give and error about consulting your operator. Basicaly it runs an XML script that conains instructions/commands to tell where to change variables in phone (some settings), where to copy some files (eg. vodafone images/sounds) etc. It MUST match the localization of the FS. (europe 3 etc).

CDA number : Quote from gsm-ware

This “number” defines which variant of a specific firmware a phone is supposed to have.It lets among others SEUS (Sony Ericsson Update Service) know which language-pack/branding/bandlocks a phone is to be flashed with. A generic (unbranded) K750 for use in Scandinavia will be CDA102337/12, whilst a Telenor-branded K750 will be CDA102338/62. Both will be flashed with the same languages/dictionaries, but the latter will be flashed with Telenor-branded firmware.

note : From my experience, you can flash most combinations of MAIN+FS (only thing to remember : your Main file to be the same platform and cid as FS. I will explain later what platform and cid means.) For example : Main=k530/v630/k610/w660 will work with Fs=k530/v630/k610/w660 in any combination.

Platform (DB) : is the technology that the phone uses. Determines (or is determined) by the CPU used, GPU used, flash memory (in which MAIN and FS are stored and runed from) format-system.

CID : its number (version) determines the method used to stop any break into flash memory. In fact it's "located" right before the loader is runed to get into flash memory (if there was not any CID present, you could break into phones just by having the loader). The newer the CID version, the more secure it is and, of course, the harder to break it.

Cid colors :
Blue : phones that never been programmed with any part of software(gdfs,erom,firmware etc).
Brown : “developer phones”, used by developers for testing. Less secured.
Red: All phones found in stores are red. Red is most secured cid, security used against end-user for modding/customing any part of software found in phone.


EROM :

Erasable Read-Only Memory

A type of read-only memory chip which can be erased and programmed with new data. EROM chips are used for flash memory. See Flash Memory. EROM is also called EPROM (for erasable programmable read-only meory). EROM memory can be erased using ultraviolet light. EROM that is erased using an electrical current is known as EEPROM.

The BIOS of your PC is stored in this kind of memory. EROM stores info about how to manipulate (in any ways) data stored within flash memory (its firmware part), how all components work and relate to each-other etc.

note The difference between PCs BIOS and phone EROMs is that PCs BIOS have "incapsuled" a program that can be used to change hardware parameters.

GDFS : the memory part that contains all encrypted settings about how firmware works and main details about phone itself (IMEI, network-lock codes etc).

Quote from wikipedia

Use and Origin

GDFS (Global Data File System) is a proprietary filesystem used by Sony-Ericsson on certain of their mobile phones. Its use dates from approximately 2002.
Sony-Ericsson handsets using GDFS include those with the db2010, db2012, db2020, and db3150 hardware sets.

Contents of file system
Data stored in the GDFS includes hardware customization data (e.g. radio channel parameters, settings for display, audio circuitry etc.), security/identification data (IMEI, lock codes, etc.) and user data - sounds, pictures, SMS, phonebook, calendar and so on. Some of GDFS units ("files"), or sometimes parts of them, are protected by checksums that are stored in other GDFS units.

The GDFS also contains the Security Zone. This contains information about any SIM-locks applied to the handset.

Faults and Repair

Although the GDFS is a robust filesystem, if a handset's GDFS does become damaged or corrupted then most likely the handset will not work properly, or may not work at all. Given those handset symptoms, a GDFS problem is the common reason.

Due to the contents of a used handset's GDFS being individual (according to the use and preferences of the user), a damaged GDFS cannot be totally restored to its previous state unless it was backed up before damage occurred. A damaged GDFS is usually reset to factory settings using unofficial software tools such as XS++ or Setool.

In the image below you can find out where to find details for some things discussed above.
To do so : download xs++ from here, press "connect", then connect your phone to pc pressing "c" on your phone's keyboard.