Your post got me curious. So, I SSHed into my Rpi0 as root and use both fdisk and cfdisk to check my 32GB microSD card that boots the kali OS. LOL and behold, fdisk only detects 2 partition sans an additional free space while cfdisk reports with an additional free space (see below). Why?
Code:
[root@kali:/root 1%] # df
Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 6927372 4174564 2381200 64% /
devtmpfs 218260 0 218260 0% /dev
tmpfs 222544 0 222544 0% /dev/shm
tmpfs 222544 5836 216708 3% /run
tmpfs 5120 0 5120 0% /run/lock
tmpfs 222544 0 222544 0% /sys/fs/cgroup
/dev/mmcblk0p1 62358 21626 40732 35% /boot
tmpfs 44508 0 44508 0% /run/user/0
[root@kali:/root 2%] # fdisk /dev/mmcblk0
Welcome to fdisk (util-linux 2.32.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
Command (m for help): p
Disk /dev/mmcblk0: 29 GiB, 31104958464 bytes, 60751872 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xb96ca1f4
Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 1 125000 125000 61M c W95 FAT32 (LBA)
/dev/mmcblk0p2 125001 14334047 14209047 6.8G 83 Linux
Command (m for help): q
[root@kali:/root 3%] # cfdisk /dev/mmcblk0
Disk: /dev/mmcblk0
Size: 29 GiB, 31104958464 bytes, 60751872 sectors
Label: dos, identifier: 0xb96ca1f4
Device Boot Start End Sectors Size Id Type
>> /dev/mmcblk0p1 1 125000 125000 61M c W95 FAT32 (LBA)
/dev/mmcblk0p2 125001 14334047 14209047 6.8G 83 Linux
Free space 14336000 60751871 46415872 22.1G
┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐
│ Partition type: W95 FAT32 (LBA) (c) │
│Filesystem UUID: 2796-8BA8 │
│ Filesystem: vfat │
│ Mountpoint: /boot (mounted) │
└──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
[Bootable] [ Delete ] [ Resize ] [ Quit ] [ Type ] [ Help ] [ Write ] [ Dump ]
Quit program without writing changes