@rooty
I managed to do it to expand the system partition from 2GB to 6GB. Went into recovery mode UBports:
simbion@simbion:~/1$ adb devices
simbion@simbion:~/1$ adb pull /data/system.img
simbion@simbion:~/1$ dd if=/dev/null of=system.img bs=1M seek=6144 count=0
simbion@simbion:~/1$ e2fsck -p system.img
simbion@simbion:~/1$ resize2fs system.img
simbion@simbion:~/1$ adb push system.img /data
The process is not fast. After that, I have all the updates and applications began to be installed. It would be nice if did it in UBports when you install to select how much you need to under system.

@simbion
https://forums.ubports.com/topic/1729/set-partition-sizes-when-flashing/8

Who knows how to increase /dev/loop0 partition size ? /dev/loop0 2.0 G 1.6 232M 88% /

@advocatux . Thanks. Solve the problem. It turned out that there is not enough space in the update directory /var/cache/apt/
$ sudo mount -o remount,rw /
$ sudo mount --bind /userdata /var/cache/apt
$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo reboot
After that the keyboard began to be displayed normally.

@nightshift said in Hangs after new firmware. Nexus 5:

Could there be a dependence on the Android firmware? I have the latest of their 5.1.1, because once I tried the last of the 6.?? and it took longer to boot. What's yours?

On 5.1.1 I did not try I do not see in it sense as the system is loaded from under /dev/loop0 from the system file.img and uses android drivers as understand.

All thank you himself has understood. It turned out you need to first flash the stock firmware, make a full reset in the stock recovery and immediately run the UT installation. But now there is a new problem when you first start when you select "edge" does not display the keyboard. In place of the white square keyboard when unlocking the same problem.

@advocatux said in Hangs after new firmware. Nexus 5:

that was updating your device or you were trying to install UT for the first time?

This is not the first time installing UT. Decided to reflash once again through UT. Flashed on stock firmware and then through UT chose a stable branch of UT. After flashing IT via the phone hung on the logo.

Hangs after new firmware. Nexus 5 does not boot after installation via ubports-installer on linux. Hangs on the nexus splash screen.