[Galaxy S II Original Android Development] sagarwadhwa1:
doing the ls /dev/block in ADB shell, i get the following:

# ls /dev/block
ls /dev/block
dm-14
dm-13
dm-12
dm-11
dm-10
dm-9
dm-8
dm-7
dm-6
dm-5
dm-4
dm-3
dm-2
dm-1
dm-0
loop14
loop13
loop12
loop11
loop10
loop9
loop8
vold
loop7
loop6
loop5
loop4
loop3
loop2
loop1
loop0
mmcblk1p1
mmcblk1
mmcblk0p11
mmcblk0p10
mmcblk0p9
mmcblk0p8
mmcblk0p7
mmcblk0p6
mmcblk0p5
mmcblk0p4
mmcblk0p3
mmcblk0p2
mmcblk0p1
platform
mmcblk0

i gues mmcblk partitions are in the open and the partition for efs is mmxblk0p1 :

i got this from the mount command:

# mount
mount
rootfs / rootfs rw,relatime 0 0
tmpfs /dev tmpfs rw,noatime,nodiratime,mode=111 0 0
devpts /dev/pts devpts rw,noatime,mode=600 0 0
proc /proc proc rw,noatime,nodiratime 0 0
sysfs /sys sysfs rw,noatime,nodiratime 0 0
none /acct cgroup rw,relatime,cpuacct 0 0
tmpfs /mnt/asec tmpfs rw,noatime,mode=755,gid=1000 0 0
tmpfs /mnt/obb tmpfs rw,noatime,mode=755,gid=1000 0 0
tmpfs /mnt/usb tmpfs rw,noatime,mode=755,gid=1000 0 0
tmpfs /app-cache tmpfs rw,noatime,size=8192k 0 0
none /dev/cpuctl cgroup rw,relatime,cpu 0 0
/dev/block/mmcblk0p2 /system ext4 rw,relatime,barrier=1,data=ordered 0 0
/dev/block/mmcblk0p1 /efs ext4 rw,nosuid,nodev,noatime,barrier=1,data=ordered 0
0
/dev/block/mmcblk0p6 /data ext4 rw,nosuid,nodev,noatime,barrier=1,data=ordered,n
oauto_da_alloc,discard 0 0
/dev/block/mmcblk0p3 /cache ext4 rw,nosuid,nodev,noatime,barrier=1,data=ordered
0 0
/dev/block/vold/179:4 /mnt/sdcard vfat rw,dirsync,nosuid,nodev,noexec,noatime,no
diratime,uid=1000,gid=1015,fmask=0002,dmask=0002,allow_utime=0020,codepage=cp437
,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro,discard 0 0
/dev/block/vold/179:9 /mnt/sdcard/external_sd vfat rw,dirsync,nosuid,nodev,noexe
c,noatime,nodiratime,uid=1000,gid=1015,fmask=0002,dmask=0002,allow_utime=0020,co
depage=cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/179:9 /mnt/secure/asec vfat rw,dirsync,nosuid,nodev,noexec,noati
me,nodiratime,uid=1000,gid=1015,fmask=0002,dmask=0002,allow_utime=0020,codepage=
cp437,iocharset=iso8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
tmpfs /mnt/sdcard/external_sd/.android_secure tmpfs ro,relatime,size=0k,mode=000
0 0
/dev/block/dm-0 /mnt/asec/pl.idreams.CanKnockdown2-1 vfat ro,dirsync,nosuid,node
v,relatime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,sho
rtname=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-1 /mnt/asec/com.smule.songify-1 vfat ro,dirsync,nosuid,nodev,relat
ime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,shortname=
mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-2 /mnt/asec/com.aldiko.android-1 vfat ro,dirsync,nosuid,nodev,rela
time,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,shortname
=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-3 /mnt/asec/com.halfbrick.fruitninjathdfree-1 vfat ro,dirsync,nosu
id,nodev,relatime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso885
9-1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-4 /mnt/asec/com.mobjoy.roadwarrior-1 vfat ro,dirsync,nosuid,nodev,
relatime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,short
name=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-5 /mnt/asec/com.learnandmaster.gibsonguitartuner-1 vfat ro,dirsync
,nosuid,nodev,relatime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=i
so8859-1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-6 /mnt/asec/com.fridgecat.android.atilt-1 vfat ro,dirsync,nosuid,n
odev,relatime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,
shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-7 /mnt/asec/com.bestcoolfungames.antsmasher-2 vfat ro,dirsync,nosu
id,nodev,relatime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso885
9-1,shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-8 /mnt/asec/com.sega.sonic4epi-1 vfat ro,dirsync,nosuid,nodev,rela
time,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,shortname
=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-9 /mnt/asec/com.whatsapp.sniffer-1 vfat ro,dirsync,nosuid,nodev,re
latime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,shortna
me=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-10 /mnt/asec/com.threed.bowling-1 vfat ro,dirsync,nosuid,nodev,rel
atime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,shortnam
e=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-11 /mnt/asec/net.explosm.cnh-1 vfat ro,dirsync,nosuid,nodev,relati
me,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,shortname=m
ixed,utf8,errors=remount-ro 0 0
/dev/block/dm-12 /mnt/asec/com.outfit7.talkingtom2-1 vfat ro,dirsync,nosuid,node
v,relatime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,sho
rtname=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-13 /mnt/asec/com.motionone.afterfocus-1 vfat ro,dirsync,nosuid,nod
ev,relatime,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,sh
ortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/dm-14 /mnt/asec/com.disney.WMW-1 vfat ro,dirsync,nosuid,nodev,relatim
e,uid=1000,fmask=0222,dmask=0222,codepage=cp437,iocharset=iso8859-1,shortname=mi
xed,utf8,errors=remount-ro 0 0
/dev/block/vold/179:9 /mnt/sdcard/gameloft vfat rw,dirsync,relatime,uid=1000,gid
=1015,fmask=0002,dmask=0002,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,
shortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/179:9 /mnt/sdcard/Android vfat rw,dirsync,relatime,uid=1000,gid=
1015,fmask=0002,dmask=0002,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,s
hortname=mixed,utf8,errors=remount-ro 0 0
/dev/block/vold/179:9 /mnt/sdcard/data vfat rw,dirsync,relatime,uid=1000,gid=101
5,fmask=0002,dmask=0002,allow_utime=0020,codepage=cp437,iocharset=iso8859-1,shor
tname=mixed,utf8,errors=remount-ro 0 0

i hope this helps :)