iPhone is stuck in Recovery Mode with full storage I was trying to update my iPhone X (GSM) from iOS 12.3.1 to iOS 14.0.1
The following steps was carried:
1- Downloading the latest firmware ipsw (size 4.61 GB) from
iPhone10,3,iPhone10,6_14.0.1_18A393_Restore.ipsw from ipsw.me
2- Downloading the latest iTunes on my Windows 10 PC
3- Connecting the iPhone by an original USB cable to my PC
4- Locating my iPhone
and pressing &quot;Shift&quot; button from my keyboard and pressing on the
Update from iTunes
5- Selected the ipsw which was previously
downloaded.
6- During in the middle of the update, an error came out
with a code # 14.
7- My iPhone got stuck permanently on the iTunes
logo
8- Tried for several times to exit the Recovery Mode by
Pressing and quickly release the Volume Up button. Press and quickly
release the Volume Down button. Then, press and hold the Side
button. it just keep restarting and getting back into the Recovery
Mode.
9- Downloaded couple of software's &quot;Tenorshare ReiBoot Pro&quot;
and &quot;3uTools&quot; to force exit Recovery Mode, no good results.
The problem here is happening because I guess that I have tried to install the updates although there was no enough storage on my iPhone.
If there is anyway to delete large files in order to free space of my iPhone (while it is in Recovery Mode&quot; it would be much appreciated.
Or
If there is a way to update the iPhone to any iOS that has a small ipsw size would help on this issue, bare in mind downgrading or using OTA (Over the Air) firmwares to be directly installed on my iPhone by a PC.
Note:

There is no back up file for the iPhone
All the documents on the iPhone are needed, therefore; restoring the iPhone is not an option as it would erase all the files and bring it to its original factory settings.
The above concern was similar to this case iPhone stuck on Apple Logo because of Storage Full, Any solution to delete some data to make it boot or backup data before restore? but there was no answer to solve the issue.

Thinking outside the box:
If there is a way to connect the iPhone to any operating system i.e. Linux and have it connected there by entering the file explorer in order to delete some large files would help, need some experiments please.
I have an idea.

get off the nand flash from the mainboard.
copy all nand flash data to a large one.
solder the large nand flash with data to the mainboard.
update new IOS with itunes.

Because changing a new larger nand flash in China is a very common thing. And there is a nand data mirroring tech in 2016 on Iphone 5C.
So I think Combine these two technologies may be can solved this problem.