Overlapping SD Card Partitions

Question

I have a 32GB SD card that I have been using for a year or so and when troubleshooting a separate issue I noticed that the partition table looks very different than the other Raspbian images I have and appears to have overlapping partitions:

Device         Boot   Start      End  Sectors  Size Id Type
/dev/mmcblk0p1         8192  2291015  2282824  1.1G  e W95 FAT16 (LBA)
/dev/mmcblk0p2      2291016 62521343 60230328 28.7G  5 Extended
/dev/mmcblk0p5      2293760  2359293    65534   32M 83 Linux
/dev/mmcblk0p6      2359296  2488319   129024   63M  c W95 FAT32 (LBA)
/dev/mmcblk0p7      2490368 62521343 60030976 28.6G 83 Linux

Normally I just see mmcblk0p1 and mmcblk0p2... Can anyone explain how to fix this and/or how this might have occurred in the first place? Or maybe this isn't even an issue?

This particular Raspbian image was made from the Jessie Lite image and the kernel is 4.4.21-v7+.

Any help is appreciated and I apologize for the somewhat vague question.

Answer 1

The partitions overlap because the last three are inside the "Extended" partition. This is used with DOS MBR style partition tables, which are limited to 512 bytes and can only information for four partitions.

DOS MBR formats are still the norm for things like USB sticks and SD cards, and the Pi firmware requires it.

In order to divide the medium into more than four partitions, the extended one is divided in logical partitions and the information about them is stored in the extended partition itself (as opposed to the 1/2 KiB MBR).

What you have looks a lot like a card formatted with NOOBS (which uses more than four partitions in order to contain multiple OS images). If you remember using it at all in the past, this is certainly a relic of that.