@advocatux I was try upade and update all system and answer is the same.
I was try it in twrp in terminal -sudo parted -l and parted -l .
The same answer.
I must go sleep. I will try discus tomorow. Tahnks for your time.

@advocatux how install complete adb on computer?

@advocatux in using : sudo adb shell (in pro5)
sudo parted -l (answer - not found)

I am usin Linux Mint - I hope this has no problem with linux synatax

@mihael in using : sudo adb shell (in pro5)
parted -l (answer - not found)

@mihael Yes, I was see in help the possibilities of fdisk.

in this :

original filesystem in PRO5 is now :
Filesystem Size Used Available Use% Mounted on
tmpfs 1.8G 156.0K 1.8G 0% /dev
tmpfs 1.8G 28.0K 1.8G 0% /tmp
/dev/block/sda43 495.9M 432.0K 485.3M 0% /cache
/dev/block/sda44 53.5G 209.0M 53.3G 0% /data
/dev/block/sda41 2.4G 1.7G 720.4M 71% /system
tmpfs 1.8G 156.0K 1.8G 0% /system/dev

is not sda42 - where is "custom" partition?

Thank you

@mihael Thanks for answer. I was detailed read.
This i can not use :
fdisk: delete the 'custom' partition (partition 42 for my meizu pro 5)
fdisk: create the 'custom' partition with a smaller size (I calculated: 512 - (700 - 512) = 512 - 188 = 324MB so that 188 would be available to add to the current size of the 'cache' partition)

I am not standrad using fdisk in LInux - Android.

How get syntax in fdisk for delete "custom" partition.
What is "custom" partition in original Flyme partitions.

Thank you

Re: How to increase cache partition ( or any partition ) on Ubuntu Touch phone? Question.

I have 1year Meizu Pro5 orig Flyme G, after complication unrooted unlocked.
The Ubuntu 15.04 (r3) installed in TWRP only from .zip file because cache for installing has only 495.9MB.

original filesystem is now :
Filesystem Size Used Available Use% Mounted on
tmpfs 1.8G 156.0K 1.8G 0% /dev
tmpfs 1.8G 28.0K 1.8G 0% /tmp
/dev/block/sda43 495.9M 432.0K 485.3M 0% /cache
/dev/block/sda44 53.5G 209.0M 53.3G 0% /data
/dev/block/sda41 2.4G 1.7G 720.4M 71% /system
tmpfs 1.8G 156.0K 1.8G 0% /system/dev

From discusion of mihael and Stefano is all understanding.

But for me nonstandard Linux user - how get fdisk command for delete custom partition and create new custom 324MB partition.
I have not on my phone -partition sda42. (which is custom partition?)
Using fdisk without experience of android partitionig can be dangerous.

Thank you for any answer.

I was buy 12/2017 Meizu Pro 5. Last version with Flyme. After month I was changed it on Ubuntu in stable version with all what standard user need. Telephone and SMS and sometimes www.
All manuals here or XDS developers not function on this machine, but any modification of these manuals make Ubuntu telefone from this. I am happy. Super super job. Thank for this informations.
After all using what I need and all is stable I have problem with USB hands free.
I dont want more use old standard S5. Now is it Ubuntu 15.04(r15)

I was logging this on SKODA Infotaiment with Bluetooth HandsFree.
All is function - logging, reading contacts, calling.
But the voice is not good codeck. You something hearing, but no usable.

I was trying in 3 versions of Ubuntu but the same.

Where I can chnge the parametres of codeck using bluetooth hands free.

Thank you