Motorola C139 V1.9.24 Won't Load from osmocom-bb

Rusty Dekema rdekema at gmail.com
Mon Apr 7 00:20:25 UTC 2014


> Given your interest in the 850 MHz band, I gather that you must be
> somewhere in North America.  Anywhere near Southern California
> perchance?

North America, yes; southern California, no. I'm in southeast
Michigan, 30-some miles from Detroit.


> Is it "official" PCS1900 support, or are you seeing some of the
> received RF energy in the PCS band (in a very strong signal area,
> presumably) seep through the imperfect 1800 MHz SAW filter with the
> antenna switch set to DCS?

That is a very good question. I am not sure yet. I will email either
you or the list again when I know more.


> If all else fails, I reason that one should be able to disassemble the
> phone, desolder the flash chip, reprogram it with a known good boot-
> loader using a standalone device programmer, then solder it back onto
> the board.  But I'm guessing that flash chip is probably a micro-BGA
> (IIRC it's a flash+pSRAM MCP), so it wouldn't be a home soldering job,
> but rather something to be sent to a professional lab.  If you fancy
> going down that road, I would suggest talking to Technotronix in
> Anaheim, California - ask for Gopal, and tell him you were referred by
> Michael S. from Harhan.

I suspect that would cost more money than I am currently willing/able
to spend on this project, but I appreciate the reference and will keep
it in mind.


> Would you mind telling us which branding it is?  It seems that Cingular
> units have bootloaders that work out of box, for Tracfones there is
> another method that has been proven to work, so what other brandings
> are out there?

Mine is Cingular branded, but it has software version 1.9.24 instead
of the seemingly better-known (and known to work) 1.0.24.


> It appears that what this tool does (at least on Tracfones with V8.8.17
> firmware) is it erases and rewrites the first 64 KiB sector of the
> flash.  The new bits written into this sector appear to be contained
> as a 65536-byte payload within the mot931c.exe binary; and it looks
> like whoever wrote this tool replaced the first 8192 bytes with a
> "good" C139/140 bootloader, while leaving the remaining 56 KiB
> unchanged from V8.8.17 firmware.  So the phone ought to retain its
> firmware unchanged, but gain the ability to break into the bootloader
> like we are used to doing.  But apparently the firmware checksums
> itself, as doing a normal boot (w/o serial download) results in a
> message on the LCD (with the backlight off, so hard to read) about
> the firmware being corrupted or something to that effect.

Very interesting, that is good to know and will come in handy if/when
I get my hands on a Tracfone that it works with.


Cheers,
Rusty




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