How to Install a Custom ROM on SAMSUNG Galaxy A51 5G (Step-by-Step Guide)

Unlocking the Bootloader

• 💡 To begin, navigate to Settings > About phone > Software information and tap Build number seven times to enable Developer options.
• 🔑 Ensure OEM unlocking is enabled in Developer options, and sign out of your Google account.
• ⚠️ Power off the phone, then boot into download mode by holding Volume Up + Volume Down and connecting the USB cable to your computer.
• 🚀 Confirm the bootloader unlock by pressing Volume Up; the phone will reset.

Preparing Files and Tools

• 💻 Download Samsung USB drivers and the AddIn tool (version 3.14.4) from hardreset.info.
• ⚙️ Install the Samsung USB drivers and restart your computer.
• 📂 Extract the AddIn tool and the custom ROM files (TWRP, LineageOS, Nick GApps) for your specific model (SM-A515F).

Flashing TWRP Custom Recovery

• 🔌 Connect your phone to the computer and launch the AddIn utility.
• 📲 In AddIn, go to the AP slot, select the TWRP file, and disable Auto Reboot and Factory Reset in the options.
• ⚡ Click Start to flash TWRP. This process is very quick.

Installing LineageOS and GApps

• 🔄 After flashing TWRP, immediately boot into recovery mode by holding Power + Volume Down until the screen turns off, then switch to Power + Volume Up.
• 🛠️ In TWRP, navigate to Advanced > Terminal, type multi-disabler, and execute it. Then, go to Wipe > Format Data, type yes, and confirm.
• 📂 Reboot back into recovery mode. Mount your phone on your computer and copy the LineageOS and Nick GApps zip files to the phone's internal storage.
• ✨ In TWRP, go to Install, select LineageOS, swipe to confirm, and then repeat the process for Nick GApps.
• 🚀 Once both are flashed, reboot the system. The initial setup may take a while.