Gti9100 Firmware 511 Download Upd May 2026

Pros:

Cons:

Install Samsung USB Drivers for Windows (or appropriate drivers for Mac/Linux).

Why bother with an old Lollipop build when Android 14 exists? Here’s why:

The subject line mentions "upd" (update). If you are trying to force an Over-The-Air (OTA) update: *

If you want to install Android 5.1.1 on your GT-I9100, here’s a short story-like guide of the typical process:

The Last Flash

The old GT-I9100 sat in a drawer, forgotten — until one evening, its owner decided to breathe new life into it. Stock Jelly Bean lagged; apps crashed. But whispers online spoke of “Lollipop 5.1.1” on XDA Developers.

First, the prerequisites:

The risky ritual began:

When the screen lit up with the colorful Lollipop lockscreen, the old phone felt new again. Not perfect — some camera glitches, battery drain — but it ran modern apps.

⚠️ Warning: Custom firmware voids warranty, risks bricking the device, and requires skill. Always follow the exact 2025/2026 XDA thread for your model (GT-I9100, not I9100G or other variants).

Official firmware for the Samsung Galaxy S II (GT-I9100) only reached Android 4.1.2 Jelly Bean Android 5.1.1 Lollipop , you must use unofficial custom ROMs like CyanogenMod 12.1 Download Sources

Since official support ended years ago, you will need to find archived files on developer community sites: Custom ROMs (Android 5.1.1): XDA Developers forum for i9100

for stable builds of LineageOS (formerly CyanogenMod) or Resurrection Remix. Google Apps (GApps): You must download a separate GApps package for Android 5.1 to have the Play Store and Google services. Official Stock Firmware:

If you need to revert to the original software (v4.1.2), sites like host original ROM files. Installation Overview

Updating to Android 5.1.1 is a manual process that typically involves these steps: Root & Recovery: Ensure your device is rooted and has a custom recovery like ClockworkMod (CWM) installed. Back up all data and specifically your EFS partition to avoid losing your IMEI/network connectivity. Wipe Device: Boot into recovery and perform a (Wipe Data/Factory Reset, Cache, and Dalvik Cache). Flash Files: Use the "Install zip from SD card" option to flash the first, followed immediately by the The first boot can take up to 10 minutes. Reflective Paper: The Longevity of the Galaxy S II

The "Legendary" S II: A Case Study in Community-Driven Device Longevity Samsung Galaxy S II (GT-I9100)

, released in 2011, represents a unique anomaly in the planned obsolescence of consumer electronics. While its official manufacturer support ended with Android 4.1.2, the device remains a "legend" in the developer community

The Samsung Galaxy S II GT-I9100 never received an official Android 5.1.1 update; its official support ended with Android 4.1.2 Jelly Bean. To run Android 5.1.1, you must install a custom ROM, which requires your device to be rooted and have a custom recovery like TWRP or CWM installed. Top Custom ROMs for Android 5.1.1 Several stable versions were developed by the community:

CyanogenMod 12.1: A widely used option based on Android 5.1.1 Lollipop.

Resurrection Remix: Known for high performance, stability, and extensive customization.

OmniROM: One of the first teams to bring a functional Lollipop experience to the S2. Preparation & Requirements

Backup: Back up all data, as the installation requires a full wipe. Battery: Ensure at least 60-80% charge. Required Files:

The Custom ROM zip file (e.g., CM 12.1 or Resurrection Remix).

GApps (Google Apps) package: Specifically the Pico version, as larger packages may fail due to the S2's limited system partition.

Recovery: A KitKat-compatible custom recovery (like CWM 6.0.4.7 or later) is necessary. Installation Steps

Transfer Files: Connect your phone to a PC and copy the ROM and GApps zip files to the root of your SD card.

Enter Recovery Mode: Power off the phone, then press and hold Volume Up + Home + Power until the recovery menu appears.

Wipe Device: Perform a Wipe Data/Factory Reset, Wipe Cache Partition, and go to "Advanced" to Wipe Dalvik Cache. gti9100 firmware 511 download upd

Flash ROM: Select Install zip from sdcard > Choose zip from sdcard, select your ROM file, and confirm.

Flash GApps: Repeat the installation step for the GApps zip file immediately after the ROM, before rebooting.

Reboot: Return to the main menu and select Reboot System Now. The first boot can take up to 5-10 minutes.

Note: If you are looking for stock firmware for recovery purposes, use the Samsung Firmware Database on SamMobile or IMEI.info to find the original 4.1.2 files for the GT-I9100.

The Samsung Galaxy S2 (GT-I9100) Go to product viewer dialog for this item.

never received an official Android 5.1.1 (Lollipop) update from Samsung. To run this version, you must use Custom ROMs such as CyanogenMod (CM), Resurrection Remix, or OmniROM. 📥 Download Links (Historical Sources)

Because this device is over a decade old, many original download links are archived or hosted on community forums.

CyanogenMod 12.1 (Unofficial): Search XDA Developers for the "CM 12.1 GT-I9100" thread.

Resurrection Remix: A stable 5.1.1 alternative known for high customization.

GApps (Google Apps): Required to use the Play Store. Use the Open GApps project selecting ARM, 5.1, and Pico or Nano versions. 🛠️ Installation Requirements

Before starting, ensure your device is prepared to avoid bricking: Backup Everything: All data will be wiped. Root & Recovery: Your Go to product viewer dialog for this item.

must be rooted and have a custom recovery like TWRP or ClockworkMod (CWM) installed. Battery: Charge to at least 80%.

PIT File (Optional): You may need a larger PIT file to repartition your storage if the system partition is too small for modern ROMs.

It seems you’re looking for the GT-I9100 (Samsung Galaxy S II) firmware version 5.1.1 to download and update your device.

However, it’s important to clarify:

Would you like a step-by-step guide for installing a custom 5.1.1 ROM, or help finding a stable older stock firmware (4.1.2) instead?

Android 5.1.1 Lollipop was never officially released by Samsung for the classic Galaxy S2 (GT-I9100). The manufacturer stopped official firmware support at Android 4.1.2 Jelly Bean. Enthusiasts must rely on Custom ROMs to run Android 5.1.1 on this specific hardware.

Reliable pathways to download and flash Android 5.1.1 on the GT-I9100 are detailed below. ⚠️ Critical Pre-Installation Warnings

Model Specific: These packages are strictly for the international GT-I9100. Do not attempt to flash them on the GT-I9100G, SGH-T989, or any other regional variant as it will permanently brick the device.

Root & Recovery Required: The smartphone must already be rooted with a compatible custom recovery (like CWM or TWRP) installed.

Data Wipe: Moving from older stock Samsung TouchWiz firmware to an Android 5.1.1 AOSP custom ROM requires formatting the system and internal storage. Back up all critical files first. 📥 Top Android 5.1.1 Custom ROMs for GT-I9100

Because official servers for these older projects may be offline, the primary hubs to find mirror links and active developer threads are the XDA Forums Galaxy S2 Hub or community-maintained mirrors on AndroidFileHost Samsung Galaxy S2 Files . 1. CyanogenMod 12.1 (Unofficial)

Overview: The most popular base for Android 5.1.1 builds on this legacy hardware.

Experience: Provides a clean, lightweight, and bloatware-free experience that mimics stock Google Android UI.

Where to look: Search the specific XDA S2 Android Development section for CM 12.1 threads featuring active download mirrors. 2. Resurrection Remix (Lollipop Edition)

Overview: A feature-dense ROM combining the speed of CyanogenMod with heavy layout customizability.

Experience: Extends the usability of the Galaxy S2 with highly optimized CPU governors to manage the older hardware. 3. SlimLP (Android 5.1.1)

Overview: Focused on shedding unnecessary framework weights to run flawlessly on devices with lower RAM footprints like the S2.

Experience: Exceptional battery retention compared to other heavy Android 5.1.1 ports. Verified builds can still be sourced via the AndroidFileHost Slim ROMs repository. 🛠️ Step-by-Step Flashing Procedure Cons: Install Samsung USB Drivers for Windows (or

Follow these sequential steps precisely after downloading the ROM .zip file and the corresponding Lollipop GApps .zip (Google Apps) file.

Transfer Files: Connect the Galaxy S2 to a PC via USB and move both downloaded .zip files directly to the root directory of the phone’s internal storage or external SD card.

Boot to Recovery: Power off the device entirely. Hold down the Volume Up + Home + Power buttons simultaneously until the recovery menu screen displays.

Perform a Full Wipe: Navigate using the volume keys and select the Power button to execute a Wipe Data / Factory Reset.

Clear Cache Data: Select Wipe Cache Partition and go to advanced settings to trigger a Wipe Dalvik Cache.

Flash the Firmware: Return to the main recovery menu, click Install Zip, find your downloaded ROM .zip file, and confirm the installation.

Flash Google Apps: Once the ROM is complete, repeat the installation process for the GApps .zip file without rebooting first.

Reboot: Select Reboot System Now. Note that the initial boot cycle after upgrading Android versions can take up to 10 minutes to load completely.

To narrow down exactly what you need for this specific device, let me know: Do you have CWM or TWRP recovery already installed?

Samsung Galaxy S2 (GT-i9100) Go to product viewer dialog for this item.

officially peaked at Android 4.1.2 (Jelly Bean). However, for those seeking Android 5.1.1 (Lollipop), the most "interesting piece" of software available is the Resurrection Remix ROM. This custom firmware breathed new life into the aging device by bringing a stable and highly customizable Lollipop experience to a phone that otherwise would have been obsolete. Key Highlights of Android 5.1.1 for GT-i9100

Resurrection Remix (Android 5.1.1): This ROM was widely celebrated for its stability, performance, and massive array of customization options on the S2. Advanced Hardware Longevity: Despite its age, the Go to product viewer dialog for this item.

became a cult classic in the development community, with some developers even porting Android 10 to the device years later.

Flashing Tool: To install these updates, users typically use Odin 3, a leaked internal Samsung tool for flashing firmware, recoveries, and bootloaders. Prerequisites for Downloading and Updating

If you are looking to update an old S2 to 5.1.1 today, you will need to follow a custom path, as official updates Samsung stopped long ago:

Custom Recovery: You must first flash a custom recovery like TWRP or CWM using Odin.

The ROM File: Locate a reliable download for the Resurrection Remix or similar Lollipop-based ZIP package from developer forums like XDA or archives like SamMobile for the base stock firmware.

Wipe Data: Perform a factory reset and system wipe within the custom recovery to ensure a clean installation.

Flash ROM & GApps: Install the ROM ZIP and a corresponding "GApps" (Google Apps) package to regain access to the Play Store and other Google services.

Caution: Modifying firmware carries risks; ensure your device is charged to at least 80% and that you have backed up all critical data before proceeding.

Disclaimer: This guide is for educational purposes only. The Samsung Galaxy S II (GT-I9100) is a legacy device released in 2011. Modifying system software carries risks, including potential data loss, voiding warranties (if applicable), or "bricking" the device. Proceed at your own risk.

Yes, with caveats. Installing Android 5.1.1 on your GT-I9100 via a custom ROM will not make it a 2023 flagship. The phone will still lag with heavy apps like Facebook or modern 3D games. However, for basic tasks (calls, SMS, light web browsing, music, YouTube at 480p), the gti9100 firmware 5.1.1 breathes essential life into an otherwise obsolete device.

If you are looking for even better performance and modern app support, consider Android 7.1 (Nougat) or Android 9 (Pie) builds for the I9100, but they are less stable. For a balance of stability and app support, 5.1.1 remains the best "final" firmware for the Galaxy S II.

Disclaimer: Modifying your device's firmware voids any remaining warranty (none for this device anyway) and carries a risk of bricking your phone. The author and sources mentioned are not responsible for any damage to your device. Proceed at your own risk. Always verify checksums (MD5) of downloaded files to ensure integrity.

The Samsung Galaxy S2 (GT-I9100) never received an official Android 5.1.1 (Lollipop) update from Samsung; its official support ended with Android 4.1.2 Jelly Bean. To run Android 5.1.1 on this device, you must use custom ROMs developed by the Android community.  Firmware Overview  Official Version: Android 4.1.2 (Jelly Bean).

Custom Version: Android 5.1.1 (Lollipop) via ROMs like CyanogenMod 12.1 or Resurrection Remix.

Prerequisites: You must have a custom recovery (like TWRP) and a repartitioned internal storage (using a PIT file), as the original system partition is too small for Lollipop.  Popular Custom ROMs for Android 5.1.1 

CyanogenMod 12.1 (CM12.1): This is the most common base for Lollipop on the GT-I9100. It offers a near-stock Android experience with added customization.

Resurrection Remix: Known for being feature-rich, this ROM combines code from CyanogenMod, Omni, and SlimROMs. If you want to install Android 5

LineageOS: While LineageOS usually starts at version 13 (Android 6.0), some unofficial builds of its predecessor (CM) are the primary way to get 5.1.1.  Installation Process (High-Level) 

Backup Data: Use titanium backup or similar tools, as this will wipe the phone.

Install Custom Recovery: Flash TWRP (Team Win Recovery Project) via Odin.

Repartition (Critical): Use a PIT file to increase the /system partition to at least 1GB. Without this, the 5.1.1 firmware will fail to install due to "Status 7" errors.

Flash Firmware: Boot into TWRP, "Wipe" data/cache, and "Install" the .zip firmware file from an SD card.

GApps: Install a "Pico" or "Nano" Google Apps package specifically for Android 5.1 (ARM architecture) if you want the Play Store.  Where to Download 

The most reliable source for these files is the XDA Developers Forum for Galaxy S2. Look for "Stable" builds in the "Original Android Development" section. Avoid third-party "firmware update" sites that require surveys, as they often contain malware or incorrect files. 

Official firmware for the Samsung Galaxy S2 (GT-I9100) Go to product viewer dialog for this item.

never reached Android 5.1.1 Lollipop; the last official release for this device was Android 4.1.2 Jelly Bean. To run Android 5.1.1 or newer on this hardware, you must use a Custom ROM developed by the community. Popular Android 5.1.1 Custom ROMs

Because these are community-developed, stability can vary. Below are the most reputable options for the

Resurrection Remix: Highly regarded for its performance, stabilization, and deep customization options. CyanogenMod 12.1 (CM 12.1)

: A classic choice, though some versions had reported bugs like non-functional Wi-Fi. The "CM12.1S" build is often cited as one of the better Android 5.1 options for this specific device.

OmniROM: Another widely used alternative that brought Lollipop features to the Prerequisites for Installation

Before attempting to flash a custom ROM, ensure the following are prepared: Device Model: This guide is strictly for the international . Do not attempt these steps on variant models like the Go to product viewer dialog for this item.

Battery: Charge your device to at least 80% to prevent it from shutting down mid-process.

Root & Recovery: Your device must be rooted with a custom recovery like CWM (ClockworkMod) or TWRP installed.

Backup: Perform a full backup using your custom recovery's "Backup" feature, as this process will wipe all data. General Installation Procedure

While specific steps may vary by ROM, the standard method for installing Android 5.1.1 on the follows this flow:

The Samsung Galaxy S II (GT-I9100) officially only supports up to Android 4.1.2 (Jelly Bean). To run Android 5.1.1 (Lollipop), you must use a third-party custom ROM, as there is no official 5.1.1 firmware from Samsung for this model. Installation Overview

Updating to 5.1.1 involves replacing the stock software with a custom ROM like CyanogenMod 12.1. Preparation:

Backup: Back up all important data as the process will wipe your phone. Drivers: Install the Samsung Mobile USB Drivers on your PC.

Root & Recovery: Your device must be rooted and have a custom recovery like TWRP installed. Download Necessary Files:

ROM: A stable build of Android 5.1.1 (e.g., CyanogenMod 12.1).

GApps: Google Apps package for Android 5.1.1 (required for the Play Store).

Odin: Use Odin 3 on your PC if you need to flash a base firmware or custom recovery first. Flashing Steps:

Transfer the ROM and GApps .zip files to your phone's internal storage or SD card.

Boot into Recovery Mode (typically Power + Home + Volume Up). Wipe the system, data, cache, and Dalvik cache.

Select Install and flash the ROM zip file, followed by the GApps zip file. Reboot the device. The first boot may take several minutes. Important Note on Stability

While Android 5.1.1 is functional, some users have successfully upgraded the GT-I9100 to even newer versions like Android 6.0 (Marshmallow) or Android 10 using similar custom ROM methods for better performance on modern apps.

Warning: Flashing firmware carries risks. If the wrong file is flashed, you can "brick" your device. Ensure your battery is charged above 50%.