Update via Blue screen written in Korean

[Star_girl]

Hi,

 Sorry for the long weird title, today I attempted to clear data cache from the hidden menu on my S24U. I have attached my S24U to the Note20U via the USB C cable and both phones were turned off, the S24U turned on and accidentally I accessed the light blue screen written in Korean language and the only thing written in English was not to turn off my phone while the software is updating. I have waited a few minutes and finally the update was done and the phone turned on by itself, all this happened while the phones were connected to each other via the USB cable. 

I have two questions here:

1. I don't know which phone updated because both seemed to go through an update during this.

2. What kind of update was it? Nothing seems to be changed on either phone tbh.

Ps. I have managed to clear the data cache on both phones psuccessfully😀 

Thank you

[lminvti]

Hi there 👋

I guess you entered "Download mode"

[Star_girl]

I don't even know what buttons I pressed, I just went with it because I didn't want to break my phone...

[lminvti]

Its used for lots of things better not mess with it as it could sometimes brick phone
https://www.samsung.com/us/support/troubleshooting/TSG01212623/

[Star_girl]

Yes, I guess nothing happened, I just let the phone do it's own thing undisturbed.