Hello,
here a quick HowTo to install gemian beside a licensed SailfishOS on the PDA.

I use a Scatter file from planet partitioning tool with following settings:

First: SailfishOS
Second: recovery
Third: empty (it seems, that there also is the sailfishos_boot.img flushed like at First)
Fourth: TWRP

After downloading all files from Planet and Jolly i modified the content of the .../etc/sysconfig/init from the ramdisk on the sailfishos_boot.img:
CODE
# Common settings for normal and recovery init.

# Amount of space to keep unallocated for refilling root or home later on.
LVM_RESERVED_MB=20480

# Default size for root LV
LVM_ROOT_SIZE=4096


Then i rebuild the ramdisk and the sailfishos_boot.img.
After installation there is 20G free space on the sailfish LVM.

On SailfishOS i create a new logical volume named gemian on the free space:
CODE
lvcreate -v -ay -Ay -l 100%FREE -n gemian sailfish


Next i extracted the latest linux-boot-lvm-stretch.img and gemian-stretch.img.xz from Adam Boardman (see the thread Final call for TP3) many thanks to Adam.
CODE
xzcat gemian-stretch.img.xz | dd of=/dev/sailfish/gemian bs=1024k
dd if linux-boot-lvm-gemian.img of=/dev/disk/by-partlabel/boot2 bs=1024k # 1)

And expand the filesystem on /dev/sailfish/gemian
CODE
e2fsck -f /dev/mapper/sailfish-gemian
fsadm resize /dev/sailfish/gemian


Then reboot the PDA using the silver Button to the installed system.

1) It should also be possible to change the filename at boot2 from sailfishos_boot.img to linux-boot-lvm-gemian.img at the Scatter file,
then it should be not necessary to write the stretch boot image on SailfishOS to /dev/disk/by-partlabel/boot2.

Many thanks to all who make this possible biggrin.gif

Gabriel