might be this problem - in my case, it was

https://forum.xda-developers.com/nexus-7-2013/nexus-7-2013-qa/accelerometer-compass-t3383223

How does ubports rotate the screen? Is there a documentation?

Strange - since now no more rotation.

The last days i used mainly terminal and ubports forum. I think rotation stopped, when i tested watching a video in morh browser

@eichenbast I just found a thread, that this 30 partitions are very normal in android???
https://forum.xda-developers.com/nexus-7-2013/general/guide-repartition-nexus72013-to-t3599907

I guess UBports is using only p1 for recovery and p30 for the rest - everything else is unused from UBports??

So I guess I dont need twrp - I boot into UBports recovery and run from the PC

adb push parted /
adb shell
~ # chmod +x parted
~ # /parted /dev/block/mmcblk0

??? and delete all partitions exept p1 ????

and my next question - is there a possibility for dual boot with postmarket os? I think, UBports is more advanced, but I am more familiar with Alpine Linux than with ubuntu...

Sorry i have no android experience....you mean i install twrp and delete there partitions and reinstall ubuntu touch?

Something like gparted is not available in ubuntu touch?

I bought a Nexus 7 on eBay that was broken and did not boot. Android recovery didn't work but Ubuntu touch fortunately installed without problems.
At the first analysis the hard disk is formatted in a strange way.

Disk /dev/loop0: 2 GiB, 2097152000 bytes, 4096000 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/loop1: 120,9 MiB, 126738432 bytes, 247536 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mmcblk0: 28,8 GiB, 30937186304 bytes, 60424192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 98101B32-BBE2-4BF2-A06E-2BB33D000C20

Device            Start      End  Sectors  Size Type
/dev/mmcblk0p1   131072   306143   175072 85,5M Microsoft basic data
/dev/mmcblk0p2   393216   399359     6144    3M unknown
/dev/mmcblk0p3   399360   405503     6144    3M unknown
/dev/mmcblk0p4   524288   554287    30000 14,7M Linux filesystem
/dev/mmcblk0p5   655360   656919     1560  780K unknown
/dev/mmcblk0p6   656920   658479     1560  780K unknown
/dev/mmcblk0p7   786432   787991     1560  780K unknown
/dev/mmcblk0p8   787992   794135     6144    3M unknown
/dev/mmcblk0p9   917504   920503     3000  1,5M unknown
/dev/mmcblk0p10  920504   923503     3000  1,5M unknown
/dev/mmcblk0p11  923504   927599     4096    2M unknown
/dev/mmcblk0p12  927600   937839    10240    5M unknown
/dev/mmcblk0p13  937840   938863     1024  512K unknown
/dev/mmcblk0p14 1048576  1081343    32768   16M unknown
/dev/mmcblk0p15 1179648  1180671     1024  512K unknown
/dev/mmcblk0p16 1180672  1180673        2    1K unknown
/dev/mmcblk0p17 1180674  1183673     3000  1,5M unknown
/dev/mmcblk0p18 1183674  1187769     4096    2M unknown
/dev/mmcblk0p19 1187770  1198009    10240    5M unknown
/dev/mmcblk0p20 1198010  1199033     1024  512K unknown
/dev/mmcblk0p21 1199034  1200057     1024  512K unknown
/dev/mmcblk0p22 1310720  3031039  1720320  840M Linux filesystem
/dev/mmcblk0p23 3031040  4177919  1146880  560M Linux filesystem
/dev/mmcblk0p24 4194304  4196351     2048    1M unknown
/dev/mmcblk0p25 4325376  4345855    20480   10M unknown
/dev/mmcblk0p26 4456448  4456463       16    8K unknown
/dev/mmcblk0p27 4456464  4456479       16    8K unknown
/dev/mmcblk0p28 4456480  4456481        2    1K unknown
/dev/mmcblk0p29 4587520  4587583       64   32K unknown
/dev/mmcblk0p30 4718592 60424158 55705567 26,6G Linux filesystem

Do I have a possibility to correct this

I am very new - just flashed yesterday. My nexus 7 deb has no troubles - works perfect.