Get it here
Software For BlackBerry Curve 8310 (TM)
BlackBerry Handheld Software v126.96.36.199 (Chinese)
Package Version: 188.8.131.52
Software Platform: 184.108.40.206
File name: 8310CJK_PBr4.5.250_rel28_PL220.127.116.11_A18.104.22.168_chin ese.exe
File size: 93.77MB
This OS can be installed on ANY 8310 regardless of brand.
1. Make sure you have the latest version of Desktop Manager installed. Currently, the latest version available is 4.3 and may be downloaded here: http://www.blackberry.com/go/softwaredownloads
Note: Desktop Manager 4.3 still has some issues. Desktop Manager 4.2 SP2 is recommended but 4.3 can be used if desired.
2. Download the above file to the PC then install it to the PC by running the file you downloaded.
3. Locate the vendor.xml file and delete it. It is located at C:\Program Files\Common Files\Research in Motion\Apploader
4. Plug in the BlackBerry and open Desktop Manager. You should be prompted to upgrade.
The process takes about 45 minutes to an hour depending on how much data you have to backup and restore during the process. Once it's done loading the new OS it will reboot (it may do this twice during the entire process.) You will see a white screen with an hourglass for up to 20 minutes at a time while the DM says "waiting for initialization." Don't unplug from the PC & Don't remove the battery unless the spinning hourglass has been there for 30 minutes or more. If the hourglass has been spinning for more than 30 minutes continuously you will need to wipe the device with JL_Cmder (close out of Desktop Manager during this process.) You will then end up with a white screen with small icons and an error code number like 507 or 543.
If you end up with a white screen with small icons and the number 507/543, simply connect to DM again and run application loader again and it should load the OS to the device.