Personally, I don’t install custom modem on my Samsung Galaxy S II. Usually, I will stick with the modem that comes along with the firmware. However, you might love that particular firmware but wish to upgrade the modem only. So you have to install official custom modem on your Samsung Galaxy S2 manually. What is the benefit of using custom modem? Well, one modem version does not work well for all the region’s telco. So there are several versions. Some modem might have better signal, speed, reception and coverage and some don’t. Choosing the correct one take time. You need to benchmark the 3G speed, battery consumption, signal strength… Monitor its performance for days. So I don’t change modem much unless I found it really bad (which I did not see one yet).
XXKL1 modem on XXKI4 firmware.
How to install custom modem on Samsung Galaxy S2?
There are several ways to install custom modem on Samsung Galaxy S2 ~ Odin, CWM and kitchen (on custom ROM like CheckROM).
Use Odin to install modem tar (or tar.md5) file. Just like the way to install CF-Root kernel except you put the modem file at PHONE instead of PDA in Odin.
If the modem is in CWM zip flash-able format, ClockworkMod Recovery is the tool that will help you to install the custom modem. Refer How to install update zip with ClockworkMod Recovery on Samsung Galaxy S2? (Video) guide to more information.
Finally, the easiest way ~ using KitchenPro App in CheckROM. Just mark the modem that you want for installation. Then Apply it to install. That’s all.
Download official Samsung Galaxy S2 modem here.