iFixit - Answers With Device "Samsung Galaxy S21 Plus"

Samsung Galaxy S21 Plus: My fingerprint scanner isn't working after replacing my battery

Thu, 30 Jul 2026 09:19:02 -0700

Hello! I recently replaced my Galaxy S21+ battery since it was draining very quickly, however after doing so, it seems my fingerprint scanner no longer works, instantly telling me to clean and dry the sensor when I try using it. Initially after the battery replacement, it partially worked, but then quickly stopped recognising fingerprints properly and now won't let me register at all.

⟐ Commented July 30, 2026 at 9:19 MST

Samsung Galaxy S21 Plus: Opened s21+ to replace battery + port. No longer can detect sim card.

Fri, 22 May 2026 13:12:27 -0700

Hi All,

First time opening up a phone, and I used the full kit that came with my battery. Its an s21+. I was looking to replace the battery + charging port, cause the port was on its absolute last legs, and the battery just cause. I followed the s21+ guides for battery + charging port, I think the only difference is that the loud speaker assembly + sim needed to be removed too for the charging port.

I put everything back together, but Psim is no longer detected. I use US Mobile, and my particular network can't be transfered to esim.

I have no experience so I'm just leaving some places where I may have messed up.

dipped my ifixit triangle pick into 70% iso-alc. It was a bit of a drive, and my phone was already broken open, I heard online that 90%+ is heavily advised. I dipped the pick in to introduce some alcohol to the battery adhesive, after... (next step)
I heated the phone multiple times with the iOpener. flipped the phone, and placed the iOpener on the screen side to try and loosen the battery adhesive. maybe I loosened something with all that heat application? I did it maybe 4x?
yanked heavily on the suction while trying to jam the pick under the battery. I tried to only hold the phone by its outer frame during that time (maybe I dislodged something during all those attempts?)
improper electrostatic discharge: I didn't have a band on or discharge regularly during the process
stabbed a lot of things into the sim card tray. my phones sim tray was really hard to trigger, so I tried the plastic tip tool, screwdriver heads, and finally the pointed tweezers. (maybe damaged the sim tray/internals?)
Sloppy adhesive placement: I used the ifixit cut-out frame adhesive, and applied it a little sloppily. maybe some adhesive is obstructing/shorting something towards the outer edges of the phone?

Things I've tried:

I've already tried reseating all the ribbon cables, and turning the phone on after reseating a few to see if a firmer application helped.
placed sim card in another phone. the sim card isn't the problem
draining the battery all the way, and recharging (someone on reddit said it helped with their sim detection issues)

Do you guys have any suggestions? I think at this point I may have damaged a component that allows mobile data to work. The reception bars are replaced with a crossed out circle, and it constantly says searching (SIM) around the notification bar.

Samsung Galaxy S21 Plus: Display blank but phone is working and touching fine

Wed, 07 Jan 2026 02:26:32 -0700

In the past (not too long ago), the lower part of the screen flickers with a bright white light occasionally until I increase the brightness before it stops, and recently the screen will take soo long to come on, I mean I'll have to tap several times on the screen and click the power button before the display comes alive, however, right now, the screen is blank but from muscle memory, I'm able to use the on screen fingerprint to unlock the screen so I could connect to my pc to pick files. I can open up the phone and make repairs, I just want to figure out if I need to change the screen or the connector or maybe theres something I could simply do.

Samsung Galaxy S21 Plus: How do I remove the screws holding the 5g bricks

Tue, 24 Jun 2025 04:54:11 -0700

I was taking apart my phone to do a frame swap and everything was going well until I got to the 5g bricks and they wouldn't budge and began to strip. I've tried using rubber bands glue a larger driver and nothing seems to work.

⟐ Answered June 24, 2025 at 4:54 MST

Samsung Galaxy S21 Plus: Can I replace an SM-G996U AMOLED with aftermarket AMOLED for SM-G996B?

Wed, 05 Feb 2025 13:49:17 -0700

I'd like to pick up an aftermarket screen and digitizer replacement on Amazon JP, but it indicates it's only for the international SM-G996B model (I have the USA's SM-G996U).

The featured guide here indicates there is an additional antenna cable in the midframe on the SM-G996U (USA). Does anyone have experience using an aftermarket SM-G996B AMOLED as a replacement in a SM-G996U? Is this additional cable likely to be problematic for an aftermarket screen meant for the SM-G996B?

I'm hoping it's just the seller's way of covering themselves, and would likely work just fine in my SM-G996U. Of course, speculative answers are all I can hope for, as aftermarket parts are anybody's guess.

Thank you!

⟐ Answered February 05, 2025 at 13:49 MST

Samsung Galaxy S21 Plus: Replaced charge port and back glass, now signal is weak all the time

Sat, 07 Sep 2024 22:31:56 -0700

Hi everyone, I replaced my back glass with a genuine one from ifixit and a charge port from ebay that looked to be oem. I plugged everything back in where it should have gone according to the guide and now I have no signal far more frequently than I used too. Sometimes it shows I have signal but I cannot connect to the internet. I don't believe any of the antennas are in the charge port board. The only wireless connector that had to be unplugged was the NFC charge coil I think. I replaced the board to make this phone last me longer but if it continues I'll have to get a new one. Any help is appreciated thanks!

⟐ Answered September 07, 2024 at 22:31 MST

Samsung Galaxy S21 Plus: Phone screen is black. I Have tried all restarts.

Wed, 17 Jul 2024 11:42:38 -0700

My phone went black screen overnight. It might have over heated. I have tried all the ways to restart and reboot. What else can be done to fix this issue?

⟐ Commented July 17, 2024 at 11:42 MST

Samsung Galaxy S21 Plus: Camera failed after gets in water

Fri, 21 Jun 2024 21:33:43 -0700

When I want to use the camera, there is a warning - Camera failed.

Phone was exposed to water before the problem started.

However, both front and back camera was working fine when using whatsapp video call or instagram video call.

Picture and videos cannot be capture using whatsapp or any other apps.

⟐ Answer edited June 21, 2024 at 21:33 MST

Samsung Galaxy S21 Plus: Why is led screen flashing

Thu, 13 Jun 2024 13:39:32 -0700

screen flashing different colours, not emulating images from display

Samsung Galaxy S21 Plus: Which part of the phone has to do with SIM functionality

Sat, 01 Jun 2024 08:06:24 -0700

I'm kind of having the same issue, but calls and data work. S21 plus, when i turn the phone on the screen to register comes up and does it thing, then fails, but as stated, calls still work etc. Is that a sim card reader fault or mother board issue?

And it fails after. But still have 5G and data. Does it every time I turn the phone on.

Safe mode didn’t work. But I did notice when you turn the phone on, whatever chip is under the cover is getting super super hot. I don’t know if that’s a partial short, I don’t have my air station yet to pull the cover off. But that might be the issue. Would you have an idea what chip or chip’s are under that?

⟐ Commented June 01, 2024 at 8:06 MST

Samsung Galaxy S21 Plus: Water droplet in camera lens.

Mon, 18 Mar 2024 01:08:15 -0700

Currently, my phone has camera has water droplets at the lens. What should I do? Do I need to bring it into a repair shop or is there something else I can do?

⟐ Answered March 18, 2024 at 1:08 MST

Samsung Galaxy S21 Plus: Replaced battery but charge only lasts a couple of hours.

Mon, 22 Jan 2024 04:02:45 -0700

A shop replaced the battery on Samsung galaxy s21 plus. Cellphone is over 3 years old and was used a lot daily. The new battery is better than the old one but only good for a couple of hours. I limit charge to 85%, and usually recharge at 20% but now sometimes it goes down to 14% before I notice. Why are replaced batteries so poor or is it something else? I have a new ankor charger and new quality charging cable.

⟐ Commented January 22, 2024 at 4:02 MST

Samsung Galaxy S21 Plus: Can I change power button without taking the screen off (s21 PLUS

Thu, 18 Jan 2024 12:05:55 -0700

i am wondering if i can change the power button without taking off the screen

⟐ Answered January 18, 2024 at 12:05 MST

Samsung Galaxy S21 Plus: Volume buttons stuck Need to remove them.

Mon, 08 Jan 2024 14:02:07 -0700

Hi,

I have an S21+ I want to remove the volume buttons & replace with new ones as the old ones do not function & phone is locked into safe mode. Will I need to remove the screen in order to replace just the volume buttons not the flex cable?

Thanks.

⟐ Commented January 08, 2024 at 14:02 MST

Samsung Galaxy S21 Plus: NOT Receiving LTE bands

Wed, 25 Oct 2023 00:18:03 -0700

SM-G966W is not picking up LTE bands in Canada?

⟐ Commented October 25, 2023 at 0:18 MST

Samsung Galaxy S21 Plus: Theres a green line on my screen

Mon, 23 Oct 2023 08:04:39 -0700

If i want to fix it myself do i only change the display screen or the screen with the frame?

⟐ Commented October 23, 2023 at 8:04 MST

Samsung Galaxy S21 Plus: Will the Genuine S21 Plus battery work on a non-US model?

Tue, 12 Sep 2023 21:39:08 -0700

I have an international S21 Plus (SM-G9960), and I'm thinking about replacing it's battery. I noticed that the official Samsung battery sold on iFixit is only listed for American models (SM-G996U/SM-G996U1). Would this part work with my phone? If not, where can I find an official battery for international models?

⟐ Answered September 12, 2023 at 21:39 MST

Samsung Galaxy S21 Plus: Samsung Phone Vibrates But no Display

Sun, 10 Sep 2023 06:24:54 -0700

I recently replaced the battery in my S21+ phone, When i turned it on to charge it the screen was green and only half of the touchscreen worked. I could not turn it off but i took it apart and tried to reinsert the display cable now i am getting no display at all. Please

⟐ Answered September 10, 2023 at 6:24 MST

Samsung Galaxy S21 Plus: My camera isn't working

Fri, 14 Jul 2023 15:53:01 -0700

My camera won't show up

⟐ Answer edited July 14, 2023 at 15:53 MST

Samsung Galaxy S21 Plus: No moblie data after I dropped it

Wed, 14 Jun 2023 17:00:28 -0700

I dropped my phone earlier today and my phone was working then my moblie data started tom turn off and on and now it wont connect at all. so when it hit the floor it said to check the sim tray but i dont have a physical sim only E-sim im contacting my moblie data team for a physical one to see if that will fix it or take it to a repair shop but everything else works except moblie data but i reset my phone and reset network property's and ran the diagnostics on my phone say my moblie data is working but i have no bars

My moblie data was working then it started to go in and out then completely gone

⟐ Commented June 14, 2023 at 17:00 MST