I have put the microSD into a USB adapter. It is the following unit:

/dev/sdd1 (I have found out with the command "df -h")

I run:

umount /dev/sdd

sudo fdisk /dev/sdd

d (my memory had no partitions, so I didn't need it)

n

p

1

Enter

+8M

Y

t

6

n

p

2

Enter

Enter

w