For smartphone power users who love to buy the best model, it can be hard to know the difference between Samsung flagship models. I was in such a position when considering a Samsung Galaxy S9, so I compared the different region models to figure out the differences.
The 5 major versions of the Samsung Galaxy S9
- G960F The "international" S9 available in most regions, including EMEA (Europe, Middle East, and Africa). It features an Exynos 9810 processor, which is faster on paper but has a very inefficient kernel/BSP implementation that results in worse performance and shorter battery life. The bootloader can be unlocked on most models after 7 days of use, see the Notes below for details.
- G960F/DS The dual SIM version of the international S9. Very similar to the single-SIM international S9.
- G960U The United States version of the S9. The U1 variant has specialized firmware that is compatible with all the major US carriers and their specialized features (such as VoLTE and Wi-fi calling). As a consequence, all carriers must certify the phone, so it is the last among US phones to receive updates. All bootloaders are locked. It seems possible to flash firmware from one carrier to another's model, which would enable VoLTE and other features for that other carrier (see Notes below for details). According to the GSMArena spec sheet, this has specialized LTE bands for the US market that other models lack. Unlike the variants above, the US S9 has a Snapdragon 845 processor to support CDMA carriers. The Snapdragon processor supports FM radio, has stronger third-party AOSP ROM development, features a better GPU than Exynos, and is generally more optimized for battery life than Exynos. These traits makes Snapdragon models more desirable than Exynos models.
- G9600 The Chinese/Latin American version of the S9, which also has a Snapdragon processor to support Chinese/Japanese CDMA carriers. Latin America usually receives Exynos models, but the change could be because Mexico instituted a rule requiring smartphones to receive FM radio, and the the Exynos model is not capable of that. The bootloader can be unlocked and regional firmware can be cross-flashed. Note that the Snapdragon S9 models received a bootloader update at some point (called "v2" in the modding community) that prevents downgrading to older firmware, so firmware made for v1 cannot be flashed on a phone that already installed an update containing the v2 bootloader.
- G960W The Canadian version of the S9. It looks to be based on the Chinese S9 because of the matching LTE bands. The bootloader is locked.
Notes on flashing firmware
- Each hardware version will have dozens of firmware versions (one for each country and/or carrier). You can generally flash any firmware package to hardware that supports it, regardless of the regional firmware it shipped with. This is called "cross-flashing". You would want to do this to get features from another firmware package, such as faster updates (as updates are sent out by firmware region code) and Samsung Pay (as Samsung Pay will only work on firmware from regions where it is enabled).
- Cross-flashing firmware can also be desiriable to enable carrier features on other hardware without requiring a bootloader unlock. For example, you could enable Wi-Fi calling for a particular carrier by flashing firmware from its region or its branded version of the S9.
- Many recent Samsung phones with Exynos processors have an "RMM" (Remote Monitoring and Management) security feature that prevents unlocking the bootloader for 7 days and blocks cross-flashing. RMM's bootloader unlock restriction can be circumvented and RMM can be disabled with a flashable package once the bootloader is unlocked. Snapdragon phones are not subject to these security restrictions.
- Firmware from outside the United States cannot support US carrier features like VoLTE.
- Normally, US carrier features would be enabled by flashing US firmware. However, the US has different hardware, so it is likely that US firmware will not work properly on non-US hardware. The alternative is to use root permissions to modify the firmware of a non-US model to install carrier configuration files copied from US models.
- To root the phone, the bootloader must be unlocked. Unlocking the bootloader through official means is only supported on some models of the S9 and will trip the Knox security eFuse.
- If the Knox eFuse is tripped, the Knox secure zone of the processor will be disabled. Warranty claims will be denied if the warranty center finds Knox has been tripped. Security keys in the secure zone will be wiped, and new keys cannot be stored. Software that depends on the secure zone, like Samsung Pay, will no longer function.
- Alternatively, the bootloader can be unlocked by flashing an "engineering" or "factory" bootloader. This is meant for internal testing and diagnostics and is not released to the public (although it sometimes leaks, or can be purchased illegally from shady repair shops). Once flashed, the engineering bootloader will not check firmware signatures, making the phone effectively unlocked. Previous engineering bootloaders had restrictions including temporarily disabling biometic sensors (like fingerprint and iris scanners) and reducing processor performance. Of course, this can all be reverted by flashing stock firmware and a stock bootloader, restoring the phone to its normal state with Knox still intact.
- Phones on T-Mobile US that don't support VoLTE may be in a situation where the phone can receive Band 12 LTE but not a 3G signal necessary for making calls, so all calls will fail until the user disables LTE to force the phone to roam to another carrier. This includes the inability to make 911 calls, so this reception issue can pose a safety risk. Users of international S9's on T-Mobile USA should be aware of this and be ready to disable LTE for emergency calls, or modify their firmware to support VoLTE.