I've managed to figure out how to change languages on the N8. I don't want to call it changing the product code, because it really isn't, it's basically installing the firmware of your choice containing the language of your choice onto the phone, without actually changing the product code at all. And no, you don't have to pay sites for firmware packages.
Edit: So this is going to be a pretty long and arduous process. Basically, we install Phoenix, a firmware downloader called NaviFirm, then we download the specific firmware you want, then flash the phone and install the firmware.
So let's get started.
You're gong to need two files,
Navifirm - http://rapidshare.com/files/42736334...rm-0.1-bin.zip
Phoenix - http://rapidshare.com/files/42736644....004.41526.rar
Note: If anyone needs these to be uploaded to a different file service, feel free to tell me in the thread.
**IMPORTANT** Note: Backup your files! Just to be safe, assume that everything on the phone will be WIPED. Make sure your phone is sufficiently charged!
Note: I ran this on a Windows 7 x64 machine so I don't think anyone should have any problems.
1) Install Phoenix, and while the installation is running, load up Navifirm, and find Nokia N8 (RM-596) in the left hand column. It takes a while to load the columns on the right, so be patient. Then click 11.12, then find the firmware variant you're looking for. For me, this was Taiwan Dark Grey (it shouldn't matter which color you use, but pick your own color just to be safe, I think it just changes the starting theme). Then click "all" and then click "download from FiRe". Put the files in any folder for now, we'll move them later.
Note: For anyone who needs this information, the following Chinese variants have the following languages:
Taiwan - Chinese Simplified (Pinyin), Chinese Traditional (Zhuyin), English
Hong Kong - Taiwan Simplified (Pinyin), Chinese Traditional (HK), English
Singapore - Chinese Simplified (Pinyin), Malay, Indonesian, English
I can also confirm that the Taiwanese and Hong Kong firmwares read Japanese just fine (although NOT Korean). The China PRC firmware might disable WIFI, so try to avoid it, although I'm not 100% sure about this.
2) After you install Phoenix, navigate to "Phoenix\Products\". Then make a folder called "RM-596". Move the firmware files into this folder.
3) Launch Phoenix. Click File -> Scan Product. You should see the red light in the bottom right corner blinking. After it's finished, the firmware version should show up on the bottom bar, it should say RM-596. Then click Flashing -> Firmware Update. In the "Product Code" line, click the "..." button, a new dialog box should pop up and you should see the firmware that you just downloaded. Select it, then click okay.
4) Now, click "Refurbish" towards the bottom. Phoenix should start flashing the firmware onto your phone.
5) Once it's finished, let the phone load. Once your computer detects it again, It should be safe to unplug.
**IMPORTANT** 6) First thing to do is to SET THE DEFAULT LANGUAGE TO ENGLISH. You can do this in Settings -> Phone -> Language. We must do this BEFORE you download the OVI Store App, otherwise you will get jumbled characters in OVI Store! After you download the OVI Store with the default language as English, you can change the phone back to the language you want to operate in.
7) After everything is done, you should be good to go!
Note: Couple things I found that hacks me off. NO SMART DIALING IN FIRMWARES WITH CHINESE. In the US firmware, I could click on Call, and start inputting a contact's name in T-9, this should search for the contact for me to call or message. HOWEVER this feature is NOT availiable in firmwares with the Chinese language, which is COMPLETE bullsh*t. Seriously, this can be so easily implemented with Pinyin that it's laughable Nokia has not yet implemented this universally on Symbian^3. This function came out years ago with the E-Series, and Nokia still hasn't ported it to Chinese firmwares. Bullsh*t.
Note: This does NOT change the product code, it only installs a fresh firmware onto the device, allowing you to use other languages. So when an update comes out, we may need to re-do this process.
With that being said, I hope this guide has been helpful. Feel free to ask questions in this thread for troubleshooting, I'll try my best to help.