Hi every one, I found the following on XDA developers, so I thought I would post it here to help every one who is having trouble updating from JF3. This worked for me
From what I have gathered on other forums (XDA Developers) its all to do with how your device is identifed in its product code.
I bought my Galaxy S sim free from Carphone Warehouse and I get the same "can't be upgraded" and "is already up to date" from Kies. Others on XXJF3 have however been able to update to the JM1 build through Kies.
It seems that the updated build has only been issued for "stock" ROMs. Despite buying SIM free from Carphone Warehouse my device seems to be treated as provider ROM.
There are two ways of checking what the "product code" is. On your device use the code *#272*HHmm# (where HHmm is the current time in 24hr format that your device is displaying. Mine says the product code is CPW (which obviously means Carphone Warehouse is being treated a provider build). Others have seen things like VDI (vodafone ireland), ORA (orange) and so on.
It seems (again from the other forums) that the stock ROMs have a product code ending in XEU (for UK - sorry I don't know the full set - go the XDA Developer forum for Galaxy S and search).
The other way to check apparently (which I haven't tried yet) is to fire up Kies, connect the Galaxy, then before doing anything else go into the Registry Editor and look for the following key:
HKey_current_user\Software\Samsun\Kies\DeviceDB\12
Note the number at the end could be anything so you will need to look through
This key you are looking for will contain the following value:
"Product Code"= "GT-I9000KHDCPW"
The CPW bit is the key information (at least for my device).
As this is an HKey_current _user setting it is only there when Kies is running and the device connected.
Now apparently (and I don't know whether this works), if you change the registry entry to the value GT-I9000HKDXEU (again only for UK) and close the registry and
then try the firmware update (all while still running Kies ovbviously), Kies will now think you have a stock ROM and offer the ROM upgrade to JM1.
I will try this when I get a chance and feed back if it works. But at least it may offer an explanation and/or workaround.
UK I9000 official firmware upgrade - Page 19 - xda-developers
I followed this and was able to update my firmware from JF3 to JM1. You don't need Root for this to work.
full thread here
http://androidforums.com/samsung-galaxy-s/150891-help-cannot-update-firmware-via-kies.html
Let me know how you get on. If you need any help PM me and I will do my best to help