我可以升级不同地区的galaxy s5固件吗

Can I upgrade galaxy s5 firmware of different region

我可以将我的 Galaxy s5 型号 SM-G900I 升级到另一个 country/region 但型号相同的固件吗?

是的!你可以。但是,要做到这一点,您需要更改 phone 的 CSC 代码。
Samsung was using an special CSC file included in Android firmware which are specifically built and designates to each country or mobile network providers.
把CSC码改成你要刷固件的对应国家的CSC就可以了!