@hummlbach thank you !
it's really interesting to see how on my smartphone, despite the smaller screen and image size, more details remain visible compared to the same image on my laptop screen .... the next laptop will be an ultra-HD xD

@flohack what do you mean with "icon in desktop file format"? on my desktop i find only .png file format.
what file extension do you need? what dimension(s)? where do I have to upload it/them?

the small details problem can be in part resolved by reducing number of (missing) airplane's parts starting from the smallest (missing) strips, but I think it's a problem only when the icon is understandable and distinguishable only thank to them.

PS: on my low-res computer screen with the image previews sizes reduced to minimum, the icon is distinguishable like the official telegram one (they both seem more to arrows than paper airplanes) and still is possible to "feel" there are some differences between them . clearly it's not possible to distinguish the details (3D, shadows etc but many of them, at this size, are not visible also in the official UT icons ) and is not possible to understand it's a "teleporting paperairplane"; but the icon seems still usable if you don't have another icon on a full blu backgroung with an arrow/paper airplane pointing top right. the same apply on the official logo if you don't have another icon with a arrow or a paperairplane on a full blu circle in backgroud.

PS2: the image above is reduced and has lost more details so use it with caution. the righter icon is the telegram official logo and I think the same icon used on smartphones.

ok, I made some design iteration based on your suggestions.

(2.2)Applying a light fold on the airplane doesn't make it more white (obviously) and we lost part of the 3D effect.
So a better way is to apply a dark fold in the lower (nearest) wing.
first iteraction:

(2.3) but here the shadow on the inner part of the airplane is wrong (shadow cast in the wrong direction)
So imho is better to apply the fold aligned on another edge of the airplane :

(2.4) here the shadow is correctly applied.

the last one is the case with two folds (I still like them):

(2.5)

@jezek If we need a single fold probably is better to maintain only the upper one because it is based on one of the main folds/lines in the airplane (as the icon guideline says). about the dark-color it is used also to make the farther wing more dark so to give a 3d effect. tomorrow i will post some iterations of the design with the light color fold applied on the top side (or dark in the lower) so we can see what is better for the 3d effect and for the icon.

about the single or the double fold honestly I didn't saw that the single fold style was the mainly used. My error.

@hummlbach I don't think a little less sharp edge would be so visible with the icon sizes. vice versa if we make them more rounded (greater radius) we risk making it difficult to understand that the element is an airplane with missing pieces. we can try to reduce the number of the missing strips so to lower the number of the sharp edges

IMHO it's fundamental that the icon resemble the original one obviously avoiding any trademark infringing. I think we can use the original "3D-ish" icon as a base and colors (so to keeping similarity with the official one and make it discernable from the Unav one) and apply on it some of the UT official graphic guideline/style so to avoid trademark infringing.
for example something like:

and

they both are in origami style. in the first the geometry and the style of the paper airplane is different from the original/official logo (it'is another paper airplane ;)). the second is more similar in terms of geometry but the teleport effect make it whole new icon.

@neopar but Ubuntu core is based on snap and at the moment there is not a snap of unity8.

I don't know if this is still a thing.
I find this:

DEV LineageOS 14.1 (Android 7.1.2) for Raspberry PI 3 B

so probably we can try to use the normal porting guidelines

In the future, for when halium will be able to handle Android8, is already available this:
DEV LineageOS 15.1 (Android 8.1.0) for Raspberry Pi 3 B and B+

both of them are done by Konsta developer

sadly both of the Raspberry Pi boards have only 1GB RAM
:-/

@lakotaubp Thank you very much! ;-)

@lakotaubp thank you.

I'm sorry but I (yet) don't have an UT so I cant use an existing wallpaper to take the info

@lakotaubp but I don't see any instruction about the wallpaper...what are the dimensions? what is the position and the radius of the circle in the welcome screen?