install.sh fails on roborock s7

[asyring]

Hi I rooted my Roborock S7 vaccum.
But I can't install the new firmware.

[root@rockrobo data]# ./install.sh 
---------------------------------------------------------------------------
 Roborock manual Firmware installer
 Copyright 2020 by Dennis Giese [dgiese at dontvacuum.me]
 Intended to work on s5e, p5, a08, a11
 Version: roborock.vacuum.a1[4|5]
 Use at your own risk
---------------------------------------------------------------------------
We are currently on rootfs1, will installing on rootfs2
check image file size
Checking integrity
./boot.img: OK
./rootfs.img: OK
Start installation ...
Installing Kernel
482+1 records in
482+1 records out
3954688 bytes (4.0 MB) copied, 0.551697 s, 7.2 MB/s
Installing OS
2448+0 records in
2448+0 records out
20054016 bytes (20 MB) copied, 2.76652 s, 7.2 MB/s
Trying to mount system
mkdir: can't create directory '/tmp/system': File exists
mount: mounting /dev/nandf on /tmp/system failed: Invalid argument
(!!!) Did not found marker in updated firmware or mount the partition (maybe XZ compressed?). Will try alternative method
23+0 records in
23+0 records out
24117248 bytes (24 MB) copied, 2.16753 s, 11.1 MB/s
./install.sh: line 71: ./unsquashfs: No such file or directory
(!!!) Did not found marker in updated firmware. Update likely failed, wont update system_a.

If I try to run unsquashfs I get
[root@rockrobo data]# ./unsquashfs -ash: ./unsquashfs: not found

Could you help me?

[root@rockrobo data]# cat /etc/os-release 
NAME="Ubuntu"
VERSION="14.04.3 LTS, Trusty Tahr"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 14.04.3 LTS"
VERSION_ID="14.04"
HOME_URL="http://www.ubuntu.com/"
SUPPORT_URL="http://help.ubuntu.com/"
BUG_REPORT_URL="http://bugs.launchpad.net/ubuntu/"
ROBOROCK_VERSION=4.1.5_1398