[HTC One A9] :
adb shell cat /proc/partitions:

major minor #blocks name

7 0 98304 loop0
179 0 15392768 mmcblk0
179 1 16 mmcblk0p1
179 2 4096 mmcblk0p2
179 3 1024 mmcblk0p3
179 4 256 mmcblk0p4
179 5 1024 mmcblk0p5
179 6 9951 mmcblk0p6
179 7 256 mmcblk0p7
179 8 24255 mmcblk0p8
179 9 512 mmcblk0p9
179 10 2048 mmcblk0p10
179 11 2048 mmcblk0p11
179 12 4096 mmcblk0p12
179 13 10240 mmcblk0p13
179 14 10240 mmcblk0p14
179 15 32 mmcblk0p15
259 0 5120 mmcblk0p16
259 1 1024 mmcblk0p17
259 2 1024 mmcblk0p18
259 3 1024 mmcblk0p19
259 4 1024 mmcblk0p20
259 5 1024 mmcblk0p21
259 6 1536 mmcblk0p22
259 7 60417 mmcblk0p23
259 8 20480 mmcblk0p24
259 9 16384 mmcblk0p25
259 10 1 mmcblk0p26
259 11 1055 mmcblk0p27
259 12 1024 mmcblk0p28
259 13 1536 mmcblk0p29
259 14 1536 mmcblk0p30
259 15 20480 mmcblk0p31
259 16 30720 mmcblk0p32
259 17 256 mmcblk0p33
259 18 1281 mmcblk0p34
259 19 16 mmcblk0p35
259 20 64 mmcblk0p36
259 21 1 mmcblk0p37
259 22 8 mmcblk0p38
259 23 512 mmcblk0p39
259 24 32768 mmcblk0p40
259 25 64 mmcblk0p41
259 26 1024 mmcblk0p42
259 27 512 mmcblk0p43
259 28 10240 mmcblk0p44
259 29 1 mmcblk0p45
259 30 46080 mmcblk0p46
259 31 10240 mmcblk0p47
259 32 512 mmcblk0p48
259 33 296960 mmcblk0p49
259 34 61440 mmcblk0p50
259 35 16384 mmcblk0p51
259 36 1024 mmcblk0p52
259 37 256 mmcblk0p53
259 38 256 mmcblk0p54
259 39 1024 mmcblk0p55
259 40 4453 mmcblk0p56
259 41 65536 mmcblk0p57
259 42 32768 mmcblk0p58
259 43 262144 mmcblk0p59
259 44 65536 mmcblk0p60
259 45 65536 mmcblk0p61
259 46 3244032 mmcblk0p62
259 47 10928128 mmcblk0p63
179 16 4096 mmcblk0rpmb
179 32 61095936 mmcblk1
179 33 61079552 mmcblk1p1

adb shell ls -l /dev/block/bootdevice/by-name:

lrwxrwxrwx root root 2016-12-04 16:58 aboot -> /dev/block/mmcblk0p12
lrwxrwxrwx root root 2016-12-04 16:58 absolute -> /dev/block/mmcblk0p51
lrwxrwxrwx root root 2016-12-04 16:58 adsp -> /dev/block/mmcblk0p24
lrwxrwxrwx root root 2016-12-04 16:58 apppreload -> /dev/block/mmcblk0p49
lrwxrwxrwx root root 2016-12-04 16:58 battery -> /dev/block/mmcblk0p47
lrwxrwxrwx root root 2016-12-04 16:58 board_info -> /dev/block/mmcblk0p1
lrwxrwxrwx root root 2016-12-04 16:58 boot -> /dev/block/mmcblk0p60
lrwxrwxrwx root root 2016-12-04 16:58 cache -> /dev/block/mmcblk0p59
lrwxrwxrwx root root 2016-12-04 16:58 carrier -> /dev/block/mmcblk0p46
lrwxrwxrwx root root 2016-12-04 16:58 cmnlib32 -> /dev/block/mmcblk0p53
lrwxrwxrwx root root 2016-12-04 16:58 control -> /dev/block/mmcblk0p35
lrwxrwxrwx root root 2016-12-04 16:58 cota -> /dev/block/mmcblk0p50
lrwxrwxrwx root root 2016-12-04 16:58 ddr -> /dev/block/mmcblk0p15
lrwxrwxrwx root root 2016-12-04 16:58 devcfg -> /dev/block/mmcblk0p4
lrwxrwxrwx root root 2016-12-04 16:58 devinfo -> /dev/block/mmcblk0p55
lrwxrwxrwx root root 2016-12-04 16:58 devlog -> /dev/block/mmcblk0p32
lrwxrwxrwx root root 2016-12-04 16:58 dip -> /dev/block/mmcblk0p5
lrwxrwxrwx root root 2016-12-04 16:58 dsp -> /dev/block/mmcblk0p25
lrwxrwxrwx root root 2016-12-04 16:58 extra -> /dev/block/mmcblk0p36
lrwxrwxrwx root root 2016-12-04 16:58 fataldevlog -> /dev/block/mmcblk0p31
lrwxrwxrwx root root 2016-12-04 16:58 frp -> /dev/block/mmcblk0p43
lrwxrwxrwx root root 2016-12-04 16:58 fsc -> /dev/block/mmcblk0p37
lrwxrwxrwx root root 2016-12-04 16:58 fsg -> /dev/block/mmcblk0p22
lrwxrwxrwx root root 2016-12-04 16:58 hosd -> /dev/block/mmcblk0p57
lrwxrwxrwx root root 2016-12-04 16:58 hyp -> /dev/block/mmcblk0p11
lrwxrwxrwx root root 2016-12-04 16:58 keymaster -> /dev/block/mmcblk0p54
lrwxrwxrwx root root 2016-12-04 16:58 keystore -> /dev/block/mmcblk0p48
lrwxrwxrwx root root 2016-12-04 16:58 limits -> /dev/block/mmcblk0p26
lrwxrwxrwx root root 2016-12-04 16:58 local -> /dev/block/mmcblk0p34
lrwxrwxrwx root root 2016-12-04 16:58 mdtp -> /dev/block/mmcblk0p58
lrwxrwxrwx root root 2016-12-04 16:58 mfg -> /dev/block/mmcblk0p7
lrwxrwxrwx root root 2016-12-04 16:58 misc -> /dev/block/mmcblk0p28
lrwxrwxrwx root root 2016-12-04 16:58 modemst1 -> /dev/block/mmcblk0p29
lrwxrwxrwx root root 2016-12-04 16:58 modemst2 -> /dev/block/mmcblk0p30
lrwxrwxrwx root root 2016-12-04 16:58 mota -> /dev/block/mmcblk0p52
lrwxrwxrwx root root 2016-12-04 16:58 pdata -> /dev/block/mmcblk0p33
lrwxrwxrwx root root 2016-12-04 16:58 persist -> /dev/block/mmcblk0p40
lrwxrwxrwx root root 2016-12-04 16:58 pg1fs -> /dev/block/mmcblk0p2
lrwxrwxrwx root root 2016-12-04 16:58 pg2fs -> /dev/block/mmcblk0p8
lrwxrwxrwx root root 2016-12-04 16:58 radio -> /dev/block/mmcblk0p23
lrwxrwxrwx root root 2016-12-04 16:58 ramdump -> /dev/block/mmcblk0p44
lrwxrwxrwx root root 2016-12-04 16:58 recovery -> /dev/block/mmcblk0p61
lrwxrwxrwx root root 2016-12-04 16:58 reserve -> /dev/block/mmcblk0p56
lrwxrwxrwx root root 2016-12-04 16:58 reserve_1 -> /dev/block/mmcblk0p6
lrwxrwxrwx root root 2016-12-04 16:58 reserve_2 -> /dev/block/mmcblk0p27
lrwxrwxrwx root root 2016-12-04 16:58 rfg_0 -> /dev/block/mmcblk0p17
lrwxrwxrwx root root 2016-12-04 16:58 rfg_1 -> /dev/block/mmcblk0p18
lrwxrwxrwx root root 2016-12-04 16:58 rfg_2 -> /dev/block/mmcblk0p19
lrwxrwxrwx root root 2016-12-04 16:58 rfg_3 -> /dev/block/mmcblk0p20
lrwxrwxrwx root root 2016-12-04 16:58 rfg_4 -> /dev/block/mmcblk0p21
lrwxrwxrwx root root 2016-12-04 16:58 rfg_8 -> /dev/block/mmcblk0p42
lrwxrwxrwx root root 2016-12-04 16:58 rpm -> /dev/block/mmcblk0p9
lrwxrwxrwx root root 2016-12-04 16:58 sbl1 -> /dev/block/mmcblk0p3
lrwxrwxrwx root root 2016-12-04 16:58 sec -> /dev/block/mmcblk0p41
lrwxrwxrwx root root 2016-12-04 16:58 sensor_hub -> /dev/block/mmcblk0p39
lrwxrwxrwx root root 2016-12-04 16:58 skylink -> /dev/block/mmcblk0p45
lrwxrwxrwx root root 2016-12-04 16:58 sp1 -> /dev/block/mmcblk0p14
lrwxrwxrwx root root 2016-12-04 16:58 ssd -> /dev/block/mmcblk0p38
lrwxrwxrwx root root 2016-12-04 16:58 system -> /dev/block/mmcblk0p62
lrwxrwxrwx root root 2016-12-04 16:58 tool_diag -> /dev/block/mmcblk0p13
lrwxrwxrwx root root 2016-12-04 16:58 tz -> /dev/block/mmcblk0p10
lrwxrwxrwx root root 2016-12-04 16:58 userdata -> /dev/block/mmcblk0p63
lrwxrwxrwx root root 2016-12-04 16:58 wcnss -> /dev/block/mmcblk0p16

Should be this one:

259 43 262144 mmcblk0p59