macbookpro-3c07540d2ff5:~ delphine$ sudo newfs_msdos -F 32 -v EFI /dev/disk0s1
WARNING: Improper use of the sudo command could lead to data loss
or the deletion of important system files. Please double-check your
typing when using sudo. Type "man sudo" for more information.
To proceed, enter your password, or type Ctrl-C to abort.
Password:
newfs_msdos: warning: /dev/disk0s1 is not a character device
512 bytes per physical sector
/dev/disk0s1: 403266 sectors in 403266 FAT32 clusters (512 bytes/cluster)
bps=512 spc=1 res=32 nft=2 mid=0xf8 spt=32 hds=32 hid=40 drv=0x80 bsec=409600 bspf=3151 rdcl=2 infs=1 bkbs=6
macbookpro-3c07540d2ff5:~ delphine$ diskutil mount disk0s1
Volume on disk0s1 failed to mount
macbookpro-3c07540d2ff5:~ delphine$ diskutil list
/dev/disk0
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *320.1 GB disk0
1: EFI 209.7 MB disk0s1
2: Apple_HFS Macintosh HD 319.7 GB disk0s2
/dev/disk1
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *1.0 TB disk1
1: EFI 209.7 MB disk1s1
2: Apple_HFS Install 999.3 GB disk1s2
3: Apple_Boot Recovery HD 650.0 MB disk1s3