iFixit - Answers With Device "Samsung Galaxy S21 Ultra"

Samsung Galaxy S21 Ultra: 3U Tools but for Samsung

Tue, 09 Sep 2025 08:42:02 -0700

Is there a software like 3U Tools but for Samsung or Android?

⟐ Answered September 09, 2025 at 8:42 MST

Samsung Galaxy S21 Ultra: Loses Cell Signal After Screen replacement

Thu, 29 Jan 2026 00:32:01 -0700

So I am testing the phone return repair the signal is working fine fore me have Data and can watch youtube videos. Checked swim card status and my Signal Strength is -107 dBm 33 asu is that bad or good Idk how to read that. Says 4G LTE

Should I reseat antenna connections or is it something else or is it working and my customer just has bad reception where they live?

⟐ Commented January 29, 2026 at 0:32 MST

Samsung Galaxy S21 Ultra: Broken Fingerprint sensor after Battery replacement

Thu, 11 May 2023 22:13:38 -0700

Followed the battery replacement guide, after installing new battery and booting, trying to register fingerprint is stuck on 0%

Tried formatting data

Tried enabling touch sensitivity

Don't have any screen protector

⟐ Answered May 11, 2023 at 22:13 MST

Samsung Galaxy S21 Ultra: I dropped my phone in my pool

Sat, 12 Aug 2023 11:52:42 -0700

My phone was underwater for about 5 minutes and it worked just fine after I got it out but then I took off my case to dry it off and I think the case was too tight and some water got in somehow when I took my case off and then my phone started to glitch and not show the screen, I put it in rice and sometimes the phone would turn on for a few minutes and i could use it normally but then the screen turned off again but I could hear the phone working from messages being sent to it, after 24 hours in rice the battery went out and I tried charging the phone and it made a weird noise and the phone wont charge, please help what should I do... I can't let my parents know a bout this they will kill me

⟐ Answered August 12, 2023 at 11:52 MST

Samsung Galaxy S21 Ultra: I have a camera failure on an S21 ultra after screen replacement?

Wed, 23 Apr 2025 17:51:56 -0700

After replacing display on S21 powered device on and went through functionality checks and front camera will not access.

⟐ Commented April 23, 2025 at 17:51 MST

Samsung Galaxy S21 Ultra: S21 ultra, yellow screen

Mon, 26 Feb 2024 23:29:53 -0700

Hi. I have a Samsung S21 ultra a friend asked me to try and repair.

When searching similar faults, I only find "black screen" Where there are a few solutions. I've tried them, except factory reset.

I was wondering I any of you, could agree with me, that the screen is faulty and needs replacement.

My friend, if it is possible, would avoid factory reset, because the device isnt backed up.

⟐ Commented February 26, 2024 at 23:29 MST

Samsung Galaxy S21 Ultra: Dropped phone in salt water pool - melted this bit, what is it?

Sat, 28 Mar 2026 09:17:12 -0700

My phone took a dip in a saltwater pool, started glitching, then got hot and powered off. Then it would not turn back on.

Came back from vacation and took it apart, disconnected most things, and finally got it to start up, enough that I could save my vacation photos.

The screen seems fine. I'd like to keep using it as a gaming phone, even if some of the accessories don't work. I do see a connector that appears blackened and melted. The ifixit teardown shows this connector on the motherboard, but the motherboard replacement guide is missing the connector. Does anyone know what it does?

⟐ Commented March 28, 2026 at 9:17 MST

Samsung Galaxy S21 Ultra: S21 ultra shut down suddenly

Sat, 30 Nov 2024 07:32:45 -0700

Hi everyone

today while i was using my phone and searching in google my phones screen went black suddenly without and any damage to the screen by fall or water and wont turn on it still vibrate but show nothing?!,but i have to mention that the temperature is so hot he!!

⟐ Commented November 30, 2024 at 7:32 MST

Samsung Galaxy S21 Ultra: How do I remove the carrier brand on my phone?

Tue, 31 Jan 2023 00:56:08 -0700

I have an S21 Ultra with a different carrier brand and bloatware. How can this be removed?

⟐ Commented January 31, 2023 at 0:56 MST

Samsung Galaxy S21 Ultra: Cracked Display sometimes works, sometimes flickers and sometimes is b

Wed, 02 Nov 2022 06:53:20 -0700

My screen is cracked bottom left, and top right corners. The screen touch works fine but the screen goes black simetimes, except the top 1/2 cm works. The screen always works when I tap once to turn on the screen saver. The screen works sometimes and it flickers sometimes too. I don't want to replace the screen.

⟐ Answer accepted November 02, 2022 at 6:53 MST

Samsung Galaxy S21 Ultra: Cracked screen flickers -temp fixes?

Thu, 26 Sep 2024 23:12:26 -0700

I broke my screen and there's a bit of glass missing on the edge. A horizontal line has appeared by the crack and the part of the screen below this often flickers green /goes dark. I found that if I play with it a bit it stops, especially I noticed if I push something fine in the crack it comes back to normal for a while (I have resorted to using the back of my earrings for this!).

I am not in a place to buy a new phone yet, and fixing this would cost about the same. My phone works perfectly besides this issue so I would like to use it as long as possible.

I've seen people suggesting to put glue or nail polish on cracked screen, but my hole is so deep I am worried this would ruin the whole screen.

Does anyone have suggestions on what I could safely put there that won't cause further damage?

Thanks !!

⟐ Answered September 26, 2024 at 23:12 MST

Samsung Galaxy S21 Ultra: Screen flashing/battery not charging

Mon, 19 Dec 2022 11:17:01 -0700

My phone got wet. It was fine and I immediately shut it off and it shutdown as normal and I dried it out. Go to cut it back on and when the battery had power it would show the charger connector symbol when it was connected and it would only boot to the OS install mode. But if connected to the charger the phone will stay on and the battery will die while connected. So I replaced all the ribbons and the battery and the ear piece section of the phone and samething. When the battery had power it would pull up the charging screen and only the Install OS mode but then it died again. I’m thinking maybe the rom was wiped somehow during shutdown causing a problem with the battery not charging. while connected. while at the same time the screen consistently flashes on and off when connected to the charger and the battery is dead. You can also feel the current vibrating while holding it when it’s plugged up. But since the digitizer is fine and it loads the OS install screen and shows the battery charger connected then the motherboard should be fine right? So if I can fix the battery situation and reinstall the rim it could fix it. I have all the soldering equipment and the know how to use it. So please tell me what I need to do. Thanks

⟐ Answered December 19, 2022 at 11:17 MST

Samsung Galaxy S21 Ultra: External audio is muffled

Mon, 31 Jan 2022 07:07:21 -0700

When I try to record audio that is played not from the phone whether it be voice or music it comes in muffled and barely audible. But music that is from the speaker is fine. Also phone calls are fine.

⟐ Answer edited January 31, 2022 at 7:07 MST

Samsung Galaxy S21 Ultra: Why is my phone isn't answering to wired earphones

Thu, 13 Mar 2025 04:43:29 -0700

When I plug my wired earphones to my phone my phone just not answering and they work on other phones but not mine, I'm so exhausted, please help

Samsung Galaxy S21 Ultra: Can internal storage be upgraded within?

Mon, 13 Apr 2026 05:46:14 -0700

I don't want to spend money on an upgrade or swap out for another phone, but my storage recently is always full and im constantly deleting and uninstalling thing's. Who want's to do that? Nobody.

If there is anyway that the ssd can be upgraded or if a memory Sim card can be installed so I can keep my phone and stop deleting/uninstalling, please please answer. I don't want to give my phone carrier more money on a different phone.

⟐ Answered April 13, 2026 at 5:46 MST

Samsung Galaxy S21 Ultra: Replaced the battery with an iFixit one and Battey life is worse

Wed, 25 Mar 2026 09:35:02 -0700

Replaced the battery on my S21 Ultra with the ones iFixit are selling on their store which was dated may 2025 (very good date) and I made the replacement in September.

Ever since then the batterylife has been either the same or even worse than before even tho i calibrated it according to the steps on the battery's package.

I have also gotten the warning in the screenshot twice since September and never seen it before that.

What's the issue?

⟐ Commented March 25, 2026 at 9:35 MST

Samsung Galaxy S21 Ultra: Screen failure after battery replacement

Tue, 27 May 2025 18:42:20 -0700

I did what I thought was a near-perfect battery replacement following IFIXIT instructions. The phone worked and I used it for the evening. Put it in the charging cradle overnight and I awoke to a dead screen. Phone still clicking as if working just nothing to see. How can my repair have caused a delayed fault like this?

⟐ Answered May 27, 2025 at 18:42 MST

Samsung Galaxy S21 Ultra: Rear back camera lens/glass cracked, any issues using 3rd party lenses

Fri, 20 Sep 2024 16:56:31 -0700

I'd like to avoid taking the entire back panel off and it seems the old camera glass can be pryed off and the new one installed. Wondering if anyone has done this/ how the 3rd party glass compares to Samsung OEM back camera lens glass?

⟐ Commented September 20, 2024 at 16:56 MST

Samsung Galaxy S21 Ultra: I dropped my phone in salt water

Tue, 29 Aug 2023 15:55:40 -0700

Recently, I dropped my phone in the salt water. It was in the water for about 5 seconds before I picked it back. But when I picked there were some lines on my phone and then later it turned completely blank[not working at all]. I took it to a nearby store to see what was wrong with it. They said there may be a screen issue and it may have to be replaced. It's gonna around $300, Is it worth getting it repaired? They said, there is no guarantee it would work fine even after fixing the screen.

⟐ Answered August 29, 2023 at 15:55 MST

Samsung Galaxy S21 Ultra: Replaced Charge Port Daughter Card what to do next?

Thu, 29 Dec 2022 08:06:36 -0700

After a power surge/outage with my phone plugged in it now cannot charge. Instead it flashes the charge indicator perpetually while draining the battery fast (all the way in under 1 minute) when plugged, can charge it wirelessly.

⟐ Commented December 29, 2022 at 8:06 MST