How to Manually Update Samsung Galaxy S21 Ultra 5G with Odin Without Data Loss

Preparing for Manual Update

• 💡 Manually updating your Samsung Galaxy S21 Ultra 5G via computer is useful if normal updates fail or are unsuccessful.
• ⚠️ It's recommended to perform a backup before starting, as there's a slight risk of data loss if you're not experienced.

Gathering Device Information

• 📌 Navigate to Settings > About phone to find your Model name (e.g., SMG998B).
• 📌 Note your Service provider software version (e.g., PLS) and the baseband version's revision (the second digit after 'XX', e.g., 'D').
• 🔑 You can only install firmware with the same or a newer revision; downgrading is not possible.

Downloading Firmware and Tools

• 🔍 Search for your specific model's firmware (e.g., SMG998B firmware) and download from a reliable source.
• 🎯 Ensure you use the correct CSC code for your region to maximize the chance of not losing data.
• 💻 Download the latest Samsung USB drivers and the Odin flashing tool (version 3.14.4 recommended) from hardreset.info.

File Preparation and Driver Installation

• 📂 Extract the downloaded firmware file, Samsung USB drivers, and Odin program.
• 🛠️ Install the Samsung USB drivers and restart your computer after installation is complete.

Flashing Firmware with Odin

• 📲 Power off your phone, then boot into Download Mode by holding Volume Up + Volume Down and plugging in the USB cable.
• 👆 Confirm by pressing Volume Up to enter Download Mode.
• 🔌 Connect your phone to the computer and open Odin.
• 📁 Load the firmware files into Odin: BL into BL, AP into AP, CP into CP, and crucially, HOME_CSC into CSC (using 'HOME_CSC' prevents data erasure, while 'CSC' will wipe your data).
• ▶️ Click Start in Odin and wait for the process to complete; your phone will restart automatically.
• ✅ After the phone reboots, you should see the lock screen, confirming the update was successful and data was retained.