Okay, I got everything ready and I am going for it.
About what you asked me:
1. You did flash a Chinese firmware? -> Yes I flashed a 4.4.2 Chinese stock firmware (I9500ZNUHNF1_I9500CHUHNF1_I9500ZNUHNF1_HOME.tar)
2. Is your download mode in Chinese? -> Yes, the download mode is in Chinese.
3. what is the size of your internal SD? -> I am not sure what do you mean by internal SD, but it is the 16GB version and the SD card is just 2GB.
I will get back here with the results to let you know how it went.