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−FFS usage on Compal phones
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−==========================
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−
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−All Compal phones (Motorola C1xx and Sony Ericsson J100) use a flash file system
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−(FFS) structure for user data.  On all currently known models with the single
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−exception of Mot C155/156, this FFS is in our familiar TIFFS format - see the
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−TIFFS-Overview article.  Mot C155/156 uses a different FFS implementation with
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−a completely different and incompatible on-flash format; it appears that the
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−name of this C155/156 FFS implementation is FMGR, as evidenced by the strings
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−found in the firmware image.
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−
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−The location of FFS within the flash on various known models is as follows:
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−
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−* On Mot C11x/12x phones with 2 MiB flash, the FFS is at 0x1F0000, using 6
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−  sectors of 8 KiB each;
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−
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−* On Mot C11x/12x phones with 4 MiB flash, the FFS is at 0x370000, using 3
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−  sectors of 64 KiB each;
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−
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−* On Mot C139/140 and SE J100 phones (4 MiB flash), the FFS is at 0x370000,
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−  using 5 sectors of 64 KiB each;
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−
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−* On Mot C155/156 phones (8 MiB flash), the FFS is at 0x700000, using 13
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−  sectors of 64 KiB each - but the format is FMGR, not TIFFS!
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−
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−In *all* of the listed cases, this FFS (be it TIFFS or FMGR) is used *only* for
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−user data, and not for anything essential.  On all of these phones you can get
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−in with fc-loadtool (our raw flash manipulation tool), erase the flash sectors
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−belonging to the FFS, exit fc-loadtool and boot the phone's regular fw with
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−totally blank FFS sectors - the fw with do a fresh FFS format (it even displays
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−a message on the LCD as it does so), and then the phone will function completely
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−normally, but be "brand new", without any previous user data.  Compal's
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−firmwares also do the same thing (automatically reformat the FFS on the first
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−boot, blowing away any old one) if you reflash from one fw version to a
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−different one, even if you don't erase the FFS sectors explicitly - Compal's
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−FFS stores the fw version that created it, and when their fw boots and sees
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−that the FFS is from a different version, they automatically do a full reformat.
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−
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−The fact that the FFS on these Compal phones is strictly non-essential and can
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−be trivially blown away and recreated implies that it does NOT store any vital
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−data: no IMEI, no RF calibration values.  Instead the IMEI is programmed into
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−the flash chip's protection register (OTP cells), whereas RF calibration values
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−and a bunch of other records which we are not able to understand are stored in
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−a completely different flash data structure of Compal's own invention: see our
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−Compal-calibration article.
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−
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−Language reset
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−==============
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−
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−There is, however, one additional issue which you need to be aware of if you
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−are going to erase the FFS and have the firmware reformat a new one: when the
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−firmware formats and writes a new FFS, the UI language is set to the firmware's
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−default, and in some fw versions it is not English.  (Both Motorola and Sony
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−Ericsson firmwares have "language pack" and "flex" parts in addition to the
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−main fw body proper.)  Sometimes one can get lucky and the default fw language
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−is English, other times the default language is non-English but still
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−intelligible enough to navigate through the menus to change it to English, but
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−I got one C118 on which the default fw language is Chinese, and I had no luck
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−in navigating through the menus to change it to English.  On that phone I had
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−to flash back the original FFS which had the English UI language setting.