IF you have a working distribution for Gemini please share with us the the kernel and secondary bootloader image (linux.bin, debian_boot.img). Unfortunately as far I have my experiences the flashing the only possibility to manage the multiboot properly and eventually both avaiable distrobutions has some conflict by default in ARM64 apt (debian with libreoffice, kali had some libraries, which seemed to be system library)... But if you can make an image for gemini users, you can use eighter the debian/kali/sailfish to have the wifi driver,audio etc what required, I am not sure if leste in a phase where we can talk about the cellular functionality, with linux wifi would be enough max 4g modem could be handy. I have read your comment and you told someone "managed" to install it if you have the flash image just send the link across