Hi Icetbr, I just tried on my Lenovo Ideapad 100s (emmc storage, 2 gigs ram) the usual deal. My USB boot disk worked fine, although I'm pretty sure it is impossible for me to slitaz on emmc storage because of manufacturer lock or something.
To create this boot disk, I used the Balena Etcher and the current Slitaz Rolling 5.0 iso. After that all I had to do was disable secure boot from bios and press F12 key to choose the boot medium. It worked like charm but again, its probably going to be hard to install it on EMMC storage (at least for me, as system doesn't even detect it once on slitaz live).
Link to iso: http://mirror.slitaz.org/iso/rolling/slitaz-rolling.iso
Link to Balena Etcher: https://www.balena.io/etcher/
P.S. the one I tried on was an entry level net book from 2016 with a restricted bios (I could only disable secure boot and everything else, user is locked out of).
Let me know if repeating the same works out for you, if you haven't tried this already.