Actually what I have done is:
sudo /sbin/fdisk /dev/mmcblk0
Welcome to fdisk (util-linux 2.29.2).
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: 7.3 GiB, 7818182656 bytes, 15269888 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: 0x92824060
Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 49152 253951 204800 100M 83 Linux
/dev/mmcblk0p2 253952 3098623 2844672 1.4G 83 Linux
/dev/mmcblk0p3 3098624 15269887 12171264 5.8G 83 Linux
Command (m for help): d
Partition number (1-3, default 3): 3
Partition 3 has been deleted.
Command (m for help): d
Partition number (1,2, default 2): 2
Partition 2 has been deleted.
Command (m for help): n
Partition type
p primary (1 primary, 0 extended, 3 free)
e extended (container for logical partitions)
Select (default p): 1
Value out of range.
p primary (1 primary, 0 extended, 3 free)
e extended (container for logical partitions)
Select (default p): p
Partition number (2-4, default 2): 2
First sector (2048-15269887, default 2048): 253952
Last sector, +sectors or +size{K,M,G,T,P} (253952-15269887, default 15269887): 15269887
Created a new partition 2 of type 'Linux' and of size 7.2 GiB.
Partition #2 contains a ext4 signature.
Do you want to remove the signature? [Y]es/[N]o: N
Command (m for help): p
Disk /dev/mmcblk0: 7.3 GiB, 7818182656 bytes, 15269888 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: 0x92824060
Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 49152 253951 204800 100M 83 Linux
/dev/mmcblk0p2 253952 15269887 15015936 7.2G 83 Linux
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Re-reading the partition table failed.: Device or resource busy
The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8).
unipi@S105-sn470:~$ sudo reboot
Reboot then:
unipi@S105-sn470:~$ sudo /sbin/resize2fs /dev/mmcblk0p2
resize2fs 1.43.4 (31-Jan-2017)
Filesystem at /dev/mmcblk0p2 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mmcblk0p2 is now 1876992 (4k) blocks long.
Now the partition seems to be ok but some thing aren't working as expected.
