Samsung Galaxy S8+ (SM-G955U) - ACG - G955USQU5CSA4 firmware
Samsung Galaxy S8+ firmware G955USQU5CSA4 is the Android 8.0.0 build for the Samsung Galaxy S8+ (model SM-G955U), released by Samsung for Nextech / C-Spire (ACG). It was built on 2 January 2019, carries the 2019-01-01 Android security patch, has changelist 15104940. The package combines system build G955USQU5CSA4 (AP/PDA) with CSC build G955UOYN5CSA4 for the ACG region code. The download is 3.9 GB and has MD5 checksum b6b97943ac7073515b9d10c28388ac6c, so you can verify the file after downloading. SamMobile added this file to the firmware archive on 28 January 2019.
How to flash G955USQU5CSA4 on the Samsung Galaxy S8+ (SM-G955U)
We recommend updating through Samsung's own tools: over-the-air (Settings › Software update) or Samsung Smart Switch on a PC. Flash the full firmware with Odin only when you are sure about the risks. A wrong region or a failed flash can brick the device, and SamMobile is not responsible for any damage.
- Download the firmware package above and extract the ZIP. It contains the AP (PDA), BL, CP and CSC files, plus a HOME_CSC file.
- Download and extract Odin on a Windows PC, and install the Samsung USB drivers if the PC does not detect the phone.
- Switch the device off and boot it into Download mode (usually Volume Up + Volume Down while connecting the USB cable, or Volume Down + Bixby + Power on older models).
- Open Odin. The ID:COM box turns blue when the device is connected.
- Load the files in their slots: BL, AP, CP and CSC. Use HOME_CSC to keep your apps and data, CSC to wipe the device.
- Leave Re-Partition unticked and click Start. The device reboots when Odin shows PASS. The first boot after a flash can take a few minutes.
Step-by-step PDFs: 5-file firmware and 1-file firmware.
What the build numbers mean
PDA / AP (G955USQU5CSA4) is the Android system build; its last three characters encode the year, month and revision. CSC (G955UOYN5CSA4) is the region and carrier configuration, and CP is the modem firmware. The product code ACG identifies the region or carrier this package was made for (Nextech / C-Spire); our list of Samsung CSC codes maps every code to its country and carrier. Flashing a package for a different product code changes carrier features and can be refused by the bootloader, so pick the one that matches the CSC shown under Settings › About phone › Software information.