How to Flash a Custom ROM on Samsung Galaxy S21 FE 5G: Step-by-Step Guide

Understanding Custom ROMs

• 💡 A custom ROM is an unofficial version of Android released by users, not the manufacturer, which can add features not found in the official firmware.
• 🚀 This video demonstrates flashing a custom ROM that includes Galaxy AI, a feature not officially available for the S21 FE, or a Pixel-like experience.

Preparation and Bootloader Unlocking

• 📌 Before starting, verify your phone's model name (e.g., SM-G990B2) and download the correct files, as linked in the description.
• ⚙️ Enable Developer Options by tapping the build number seven times in Settings > About Phone > Software Information.
• 🔓 Ensure OEM Unlocking is enabled in Developer Options. To unlock the bootloader, power off the phone, then boot into a special mode by holding both volume keys while plugging in the USB cable. Press Volume Up to confirm the unlock if prompted.

Installing Custom Recovery (TWRP)

• 💻 Download and install Samsung USB drivers and Odin (version 3.14.4 recommended) from hardreset.info.
• 📲 Boot your phone into Download Mode by holding Volume Up and Volume Down, then plugging in the cable and pressing the Power button.
• 🛠️ In Odin, load the custom recovery file (e.g., TWRP) into the AP slot, go to Options, and disable Auto Reboot.
• ▶️ Click Start in Odin to flash the custom recovery. Once complete, disconnect the cable and immediately boot into recovery mode by holding Power and Volume Up.

Flashing the Custom ROM

• 🔄 In TWRP recovery, go to Wipe > Format Data and type 'yes' to confirm. Then, perform an Advanced Wipe on Dalvik/ART Cache, Data, and Internal Storage.
• 📂 Connect your phone to the computer and transfer the custom ROM zip file to the phone's internal storage.
• ⚡ Alternatively, use ADB Sideload if direct file transfer is not possible. This involves using a terminal on your computer with ADB tools installed.
• 🚀 Select the custom ROM zip file in TWRP and Swipe to confirm the flash. This process can take a significant amount of time.

Setup and Verification

• 💻 After flashing, reboot the system. The first boot may take longer than usual.
• ✨ Once the setup is complete, you can verify the custom ROM installation by checking for new features like Galaxy AI in the settings, confirming the software appears to be a newer version.