<sub>This serves as an addition to the accepted answer and also as a potential source of possibly important facts, which were untold by the OP. This should normally not happen. **You shall not intentionally redact / hide / manually edit any command outputs like your `fdisk`**, for any reasons other than hiding some sensitive information like serial numbers, for example.</sub>

***

Today, I needed to restore some of my oldest audio collection,.. no, I did not backup my MP3s. So, I remembered I had some old Apple iPod (4GB). I plugged it into the USB, and voila, I see some very similar, and particularly strange, partitioning like the OP posted:

```none
# fdisk -l /dev/sdb

Disk /dev/sdb: 3,78 GiB, 4055885824 bytes, 1980413 sectors
Disk model: iPod
Units: sectors of 1 * 2048 = 2048 bytes
Sector size (logical/physical): 2048 bytes / 2048 bytes
I/O size (minimum/optimal): 2048 bytes / 2048 bytes
Disklabel type: dos
Disk identifier: 0x6f20736b

Device Boot Start End Sectors Size Id Type
/dev/sdb1 778135908 1919645538 1141509631 2,1T 72 unknown
/dev/sdb2 168689522 2104717761 1936028240 3,6T 65 Novell Netware 386
/dev/sdb3 1869881465 3805909656 1936028192 3,6T 79 unknown
/dev/sdb4 2885681152 2885736650 55499 108,4M d unknown

Partition table entries are not in disk order.
```

You see the resemblance?!

***

Now, how it mounts:

```none
# mount -v | grep -i sdb

/dev/sdb on /media/vlastimil/18ED-9712 type vfat (rw,nosuid,nodev,relatime,uid=1000,gid=1000,fmask=0022,dmask=0022,codepage=437,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro,uhelper=udisks2)
```

Intereestingly, as you can see, the primary file system resides on the device itself and not in those partitions we can see with `fdisk`. We could argue, that such an engineering is wrong, but Apple won't change, I suppose, so there is nothing to gain.

One example, where it would really mess things up, may be `fdisk`, and I mean you really must read the warning:

```none
# fdisk /dev/sdb

Welcome to fdisk (util-linux 2.39.3).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

The device contains 'vfat' signature and it will be removed by a write command. See fdisk(8) man page and --wipe option for more details.

Command (m for help): p

Disk /dev/sdb: 3,78 GiB, 4055885824 bytes, 1980413 sectors
Disk model: iPod 
Units: sectors of 1 * 2048 = 2048 bytes
Sector size (logical/physical): 2048 bytes / 2048 bytes
I/O size (minimum/optimal): 2048 bytes / 2048 bytes
Disklabel type: dos
Disk identifier: 0x6f20736b

Device Boot Start End Sectors Size Id Type
/dev/sdb1 778135908 1919645538 1141509631 2,1T 72 unknown
/dev/sdb2 168689522 2104717761 1936028240 3,6T 65 Novell Netware 386
/dev/sdb3 1869881465 3805909656 1936028192 3,6T 79 unknown
/dev/sdb4 2885681152 2885736650 55499 108,4M d unknown

Partition table entries are not in disk order.

Command (m for help): q
```

Let me stress it:

<strong>

> The device contains 'vfat' signature and it will be removed by a write command. See fdisk(8) man page and --wipe option for more details.

</strong>

Be sure not to hit `w` there! :)

***

When unmounted, running `fsck` is not dangerous:

```none
# fsck -fvy /dev/sdb

fsck from util-linux 2.39.3
fsck.fat 4.2 (2021-01-31)
Checking we can access the last sector of the filesystem
There are differences between boot sector and its backup.
This is mostly harmless. Differences: (offset:original/backup)
 65:01/00
 Not automatically fixing this.
Boot sector contents:
System ID "MSDOS5.0"
Media byte 0xf8 (hard disk)
 2048 bytes per logical sector
 4096 bytes per cluster
 236 reserved sectors
First FAT starts at byte 483328 (sector 236)
 2 FATs, 32 bit entries
 3952640 bytes per FAT (= 1930 sectors)
Root directory start at cluster 2 (arbitrary size)
Data area starts at byte 8388608 (sector 4096)
 988158 data clusters (4047495168 bytes)
63 sectors/track, 255 heads
 0 hidden sectors
 1980413 sectors total
Volume label 'UªIVATEL -' stored in root directory is not valid.
 Auto-removing label.
Reclaiming unconnected clusters.
Dirty bit is set. Fs was not properly unmounted and some data may be corrupt.
 Automatically removing dirty bit.
Checking free cluster summary.

*** Filesystem was changed ***
Writing changes.
/dev/sdb: 122 files, 44508/988158 clusters
```

***

I also went on checking the system log, attaching for completeness:

```none
[Sun Jan 5 20:19:47 2025] usb 1-2: new high-speed USB device number 10 using xhci_hcd
[Sun Jan 5 20:19:47 2025] usb 1-2: New USB device found, idVendor=05ac, idProduct=1302, bcdDevice= 0.01
[Sun Jan 5 20:19:47 2025] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[Sun Jan 5 20:19:47 2025] usb 1-2: Product: iPod
[Sun Jan 5 20:19:47 2025] usb 1-2: Manufacturer: Apple Inc.
[Sun Jan 5 20:19:47 2025] usb 1-2: SerialNumber: <- SN removed ->
[Sun Jan 5 20:19:47 2025] usb-storage 1-2:1.0: USB Mass Storage device detected
[Sun Jan 5 20:19:47 2025] scsi host2: usb-storage 1-2:1.0
[Sun Jan 5 20:19:47 2025] usbcore: registered new interface driver usb-storage
[Sun Jan 5 20:19:47 2025] usbcore: registered new interface driver uas
[Sun Jan 5 20:19:47 2025] usbcore: registered new device driver apple-mfi-fastcharge
[Sun Jan 5 20:19:48 2025] scsi 2:0:0:0: Direct-Access Apple iPod 2.70 PQ: 0 ANSI: 2
[Sun Jan 5 20:19:48 2025] sd 2:0:0:0: Attached scsi generic sg1 type 0
[Sun Jan 5 20:19:48 2025] sd 2:0:0:0: [sdb] 1980413 2048-byte logical blocks: (4.06 GB/3.78 GiB)
[Sun Jan 5 20:19:48 2025] sd 2:0:0:0: [sdb] Write Protect is off
[Sun Jan 5 20:19:48 2025] sd 2:0:0:0: [sdb] Mode Sense: 6e 00 00 08
[Sun Jan 5 20:19:48 2025] sd 2:0:0:0: [sdb] Incomplete mode parameter data
[Sun Jan 5 20:19:48 2025] sd 2:0:0:0: [sdb] Assuming drive cache: write through
[Sun Jan 5 20:19:48 2025] sdb:
[Sun Jan 5 20:19:48 2025] sd 2:0:0:0: [sdb] Attached SCSI removable disk
[Sun Jan 5 20:19:48 2025] FAT-fs (sdb): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.
```

***

My iPod supports only FAT32 as per from the following file:

```none
/media/vlastimil/18ED-9712/iPod_Control/Device/SysInfoExtended
```
where an excerpt states the file system:

```xml
<key>VolumeFormat</key><string>FAT32</string>
```

[FAT32 on Wikipedia][1] states, as was already said, I quote:

> **The maximal possible size for a file on a FAT32 volume is 4 GB minus 1 byte** or more exactly 2<sup>32</sup> − 1 bytes.


 [1]: https://en.wikipedia.org/wiki/File_Allocation_Table#FAT32