I've modified the XFCE 18.1-rc8 liveUSB to boot on my Asus T100CHI which has UEFI32. Calamares defaulted to my SD card (mmcblk0), but I was able to change it to use my actual on-board storage (mmcblk2) instead. This is why I triple check the partitions and use manual partitioning. The first install failed with
Boost.Python error in job "machineid".
Command 'system-machine-id-setup' died with <Signal.SIGHUP:1>.
File "/usr/lib/calmares/modules/machineid/main.py",line 64, in run check_target_env_call("*systemd-machine-id-setup")
File <"string">, line 3, in <module>
I restarted the installer (again setting efi partition (mmcblk2p1) to /boot/efi and mmcblk2p7 to /), but this time I formatted the root partition. Then the installation worked including grub (UEFI32). The machine rebooted successfully to grub menu and I selected XFCE 18.1.0-rc8 which loaded fine. Except for hacking the liveUSB to add bootia32.efi and the i386-efi grub modules (sourced from mx-linux for my fat32 liveUSB), Manjaro XFCE 18.1-rc8 (64 bit) installed as long as I formatted the root partition. The key was manual partitioning, verifying the right storage device and setting the efi partition.