While I appreciate the work - and I am not questioning the author of the guide - it is not always possible for an end-user to make it happen. See below which is shortly after this guide was created
Some users have success with it - others don’t - but it boils down to: is the device listed as removable or not.
To my knowledge Calamares is designed avoid installing to removable devices - as it could create an issue where one accidently selects the device containing the installation source.
To check if your device is listed as removable - use lsblk and list the recognized devices then check the RM column of the output.
The number 1 designates a removable device - which Calamares won’t install to.
Sample (incomplete) output from my system and as you can see it is quite arbitrary how the system see’s the devices.
- sdd is USB connected backup device (Seagate 2TB spinning HD)
- sde is USB stick (Kingston DataTraveller)
- mmcblk0 is SD-card (Transcend)
➜ ~ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
sdd 8:48 0 1,8T 0 disk
└─sdd1 8:49 0 1,8T 0 part
sde 8:64 1 14,4G 0 disk
├─sde1 8:65 1 250M 0 part
├─sde2 8:66 1 1M 0 part
└─sde3 8:67 1 14,2G 0 part
sr0 11:0 1 1024M 0 rom
mmcblk0 179:0 0 15G 0 disk
└─mmcblk0p1
179:1 0 15G 0 part
nvme0n1 259:0 0 476,9G 0 disk
├─nvme0n1p1
│ 259:1 0 300M 0 part
├─nvme0n1p2
│ 259:2 0 467,8G 0 part /
└─nvme0n1p3
259:3 0 8,8G 0 part [SWAP]