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