Leo’s Samsung Galaxy S9 Plus was a ghost in the machine. On paper, it was a 2018 flagship: a gorgeous curved AMOLED display, a versatile dual-aperture camera, and enough power for daily tasks. But in reality, it was a hot, stuttering mess.
The culprit was the Exynos 9810 processor.
While friends in the US praised their Snapdragon S9s for smooth performance and battery life, Leo’s European Exynos model would heat up scrolling through Twitter. Gaming was a lag fest. And the final insult? Samsung had pulled the plug on OS updates two years ago. He was stuck on Android 10 with a November 2020 security patch.
“It’s a paperweight with a beautiful screen,” he muttered, watching the battery drain 10% in fifteen minutes of camera use. He was about to list it on eBay for spare parts when a Reddit notification popped up: [ROM][OneUI 5.1] Noble ROM 3.0 for Exynos S9/S9+ - Faster than ever!
Leo’s heart skipped a beat. He remembered the old days: CyanogenMod on his Galaxy S2, XDA forums, and the thrill of turning a carrier-bloated brick into a lean, mean machine. But that was a decade ago. Could this tired Exynos S9 Plus really run Android 13 with One UI 5.1?
The XDA thread was a chaotic cathedral of hope and technical jargon. The OP (Original Poster), a dev named corsicanu, claimed they had backported the entire camera stack, fixed the Exynos thermal throttling, and even enabled VoLTE. The comments were glowing: “Benchmarks up 20%!” “No more overheating!” “It’s like a new phone!”
The risk was real. Flashing a custom ROM on an Exynos S9 Plus was a minefield: samsung s9 plus exynos custom rom
But the stock ROM’s lag was a slow death anyway. Leo decided to go for glory.
The Procedure:
Friday night, 11 PM. He downloaded the prerequisites: TWRP (Team Win Recovery Project) for the starlte (S9) and star2lte (S9+), the Noble ROM zip, a patched version of Magisk for root, and the latest Exynos 9810 vendor image. He backed up his photos, kissed his e-warranty goodbye, and powered down.
Volume Down + Bixby + Power. The screen flashed. He was in Download Mode. He fired up Odin on his laptop, the ancient flasher tool with its four mysterious slots: BL, AP, CP, CSC. One wrong checkmark and it was over.
He clicked “Start.”
The blue bar crawled. His palms were sweaty. At 75%, the phone rebooted into a black screen. His heart stopped. For five seconds, nothing. Then, the glowing Samsung logo flickered. He exhaled. Leo’s Samsung Galaxy S9 Plus was a ghost in the machine
He booted into TWRP, swiped to allow modifications, and formatted everything – Data, System, Cache, Dalvik. The stock ROM was dead. He then sideloaded the Noble ROM ZIP. The script ran, spitting out lines like “Patching Exynos thermal engine” and “Adjusting GPU governor.”
Finally, the message: “Script succeeded. Result was [0.200]”
He hit “Reboot System.”
The first boot on a custom ROM is always the longest. The “Samsung Galaxy S9+” logo glowed for a full three minutes. Then, the screen shimmered, and the new Android 13 setup wizard appeared. The colors were sharper. The animations were fluid. There was no stutter, no micro-lag.
The Aftermath:
The next morning, Leo ran a stress test. He played Genshin Impact at medium settings – the Exynos used to overheat in 5 minutes. He played for 30. The phone got warm, not hot. The battery graph was a gentle downward slope, not a cliff. Knox: Once tripped, Samsung Pay and Secure Folder
The camera? The developer had ported the flagship camera drivers. The variable aperture f/1.5 and f/2.4 worked perfectly, even in Pro mode. For the first time, the Exynos S9 Plus felt like the phone Samsung should have shipped.
There were quirks. Secure Folder was gone. Samsung Pass showed an error about “tampered device.” But Leo didn’t care. He flashed a custom kernel, underclocked the big cores, and managed to squeeze 5 hours of screen-on-time – two more than he’d ever seen.
He returned to XDA, not as a lurker, but as a contributor. He posted his battery stats, helped a noob fix a bootloop by telling him to “fastboot erase misc,” and sent the developer $20 for coffee.
The Samsung S9 Plus Exynos was no longer a forgotten flagship. It was a thought-provoking machine, freed from Samsung’s planned obsolescence, running on the love of strangers on the internet.
In a world of thousand-dollar foldables and AI phones, Leo realized the most powerful feature wasn’t a spec sheet. It was an unlocked bootloader.
Warning: This will void your warranty (if any remains) and wipe your data.
Before we dive into the software, let’s address the hardware. Samsung’s in-house Exynos 9810 chipset is fully documented, which means source code is available for developers. This has led to:
Best for: De-Googling.