S21 can't connect to PC via USB. Please help!!

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killerscript

Senior Member
Oct 9, 2015
59
8
A month ago I've updated my S21.
Since then, I'm unable to transfer data from my mobile to PC, AND can't connect my phone to Android Auto in my car multimedia
I tried different cables, ALL original ones but still same error:

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V0latyle

Forum Moderator
Staff member
So why I can still charge my phone like usual?
Does it make sense that I can charge my phone but can't connect it to my PC and transfer data?
Yes, because the USB connector has specific pins for data and power.

The old USB 2.0 and below used 4 pins, which were +5v, Data+, Data-, and Ground. USB-C uses 24 pins - 4 ground pins, 4 power pins, 12 data pins, etc.

A USB A to C cable has the GND pin on the A connector connected to all 4 of the GND pins on the C connector, and the VBUS pin on the A connector connected to all 4 of the VBUS pins on the C connector, but the two Data pins are only connected to the two USB 2.0 data pins (A6 and A7) on the C connector.

So, if the Data pins don't make good contact, but the VBUS and GND pins do, the phone will charge...albeit at the slow 5 volt rate. I assume when you plug it into the charger, it doesn't charge rapidly?

Make sure there isn't lint or dirt buildup in the USB port of your phone. Use a small thin plastic pick to gently scrape out any crud that might be in there around the connector. Don't use any harsh chemicals or solvents; you can use a small amount of isopropyl alcohol to help clean if necessary.
 

killerscript

Senior Member
Oct 9, 2015
59
8
Yes, because the USB connector has specific pins for data and power.

The old USB 2.0 and below used 4 pins, which were +5v, Data+, Data-, and Ground. USB-C uses 24 pins - 4 ground pins, 4 power pins, 12 data pins, etc.

A USB A to C cable has the GND pin on the A connector connected to all 4 of the GND pins on the C connector, and the VBUS pin on the A connector connected to all 4 of the VBUS pins on the C connector, but the two Data pins are only connected to the two USB 2.0 data pins (A6 and A7) on the C connector.

So, if the Data pins don't make good contact, but the VBUS and GND pins do, the phone will charge...albeit at the slow 5 volt rate. I assume when you plug it into the charger, it doesn't charge rapidly?

Make sure there isn't lint or dirt buildup in the USB port of your phone. Use a small thin plastic pick to gently scrape out any crud that might be in there around the connector. Don't use any harsh chemicals or solvents; you can use a small amount of isopropyl alcohol to help clean if necessary.
I see, thank you for the deeper explanation.
Although, I found a bypass solution which I don't understand how it works:
I took a UGREEN hub that I bought from Aliexpress a few years ago, I plugged the Type C connector to my S21, I took a 128GB Flash Drive and connected it into the HUB and guess what? it worked! so I managed to backup files from my S21 to my USB Drive via the HUB I put between them.

I still don't understand how it worked and why it doesn't with a direct connection of my phone to my Laptop..
The cables are great and Samsung original ones.
Also, 1 of the 2 cables is new, I bought it a month ago.
 

V0latyle

Forum Moderator
Staff member
I see, thank you for the deeper explanation.
Although, I found a bypass solution which I don't understand how it works:
I took a UGREEN hub that I bought from Aliexpress a few years ago, I plugged the Type C connector to my S21, I took a 128GB Flash Drive and connected it into the HUB and guess what? it worked! so I managed to backup files from my S21 to my USB Drive via the HUB I put between them.

I still don't understand how it worked and why it doesn't with a direct connection of my phone to my Laptop..
The cables are great and Samsung original ones.
Also, 1 of the 2 cables is new, I bought it a month ago.
Are you sure it isn't a problem with your computer? You said connecting your phone to your car doesn't work either, correct?
 

killerscript

Senior Member
Oct 9, 2015
59
8
Are you sure it isn't a problem with your computer? You said connecting your phone to your car doesn't work either, correct?
I'm sure because i can connect other devices to my computer :/
And yeah I cant connect my phone to my car via Android Auto anymore
And the whole issue started a few days after I updatedf my firmware...
 

V0latyle

Forum Moderator
Staff member
I'm sure because i can connect other devices to my computer :/
And yeah I cant connect my phone to my car via Android Auto anymore
And the whole issue started a few days after I updatedf my firmware...
Did you use the right firmware?


If you've already cleaned the USB port the only thing I could suggest at this point is doing a factory reset and flashing the firmware again, being careful to make sure it's the right one.