[AT&T Samsung Galaxy S II Skyrocket SGH-I727] dLuck:
I tried Heimdall on Linux machine.

Executed two commands:

1. sudo heimdall detect --verbose --stdout-errors --usb-log-level debug (Description: Indicates whether or not a download mode device can be detected.)

Result:

[timestamp] [threadID] facility level [function call] <message>

--------------------------------------------------------------------------------

[ 0.003046] [00000c57] libusbx: debug [libusb_get_device_list]

[ 0.003115] [00000c57] libusbx: debug [discovered_devs_append] need to increase capacity

[ 0.003143] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003156] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003171] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003186] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003200] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003212] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003226] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003240] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003253] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003266] [00000c57] libusbx: debug [libusb_get_device_descriptor]

[ 0.003280] [00000c57] libusbx: debug [libusb_get_device_descriptor]

Device detected

[ 0.003320] [00000c57] libusbx: debug [libusb_exit]

[ 0.003335] [00000c57] libusbx: debug [libusb_exit] destroying default context​

2. sudo heimdall print-pit --verbose --stdout-errors --usb-log-level debug (Description: Prints the contents of a PIT file in a human readable format. If a filename is not provided then Heimdall retrieves the PIT file from the connected device.)

Result:

Heimdall v1.4.0

Copyright (c) 2010-2013, Benjamin Dobell, Glass Echidna

http://www.glassechidna.com.au/

This software is provided free of charge. Copying and redistribution is

encouraged.

If you appreciate this software and you would like to support future

development please consider donating:

http://www.glassechidna.com.au/donate/

Initialising connection...

Detecting device...

[timestamp] [threadID] facility level [function call] <message>

--------------------------------------------------------------------------------

[ 0.005876] [00000c5b] libusbx: debug [libusb_get_device_list]

[ 0.005970] [00000c5b] libusbx: debug [discovered_devs_append] need to increase capacity

[ 0.006011] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006038] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006066] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006096] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006123] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006149] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006176] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006202] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006232] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006260] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006287] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006317] [00000c5b] libusbx: debug [libusb_open] open 5.2

[ 0.006380] [00000c5b] libusbx: debug [usbi_add_pollfd] add fd 11 events 4

[ 0.006444] [00000c5b] libusbx: debug [libusb_get_device_descriptor]

[ 0.006481] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.006532] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.006561] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.007328] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.007377] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=0 transferred=4

[ 0.007388] [00000c5b] libusbx: debug [handle_control_completion] handling completion status 0

[ 0.007399] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.007412] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x16681f8 has callback 0x7fbb5a5c97f0

[ 0.007422] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=4

[ 0.007451] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.007480] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.007491] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.008323] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.008371] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=0 transferred=18

[ 0.008383] [00000c5b] libusbx: debug [handle_control_completion] handling completion status 0

[ 0.008395] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.008407] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x16681f8 has callback 0x7fbb5a5c97f0

[ 0.008418] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=18

Manufacturer: "Sasmsung"

[ 0.008446] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.008473] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.008484] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.009174] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.009197] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=0 transferred=4

[ 0.009207] [00000c5b] libusbx: debug [handle_control_completion] handling completion status 0

[ 0.009216] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.009226] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x16681f8 has callback 0x7fbb5a5c97f0

[ 0.009236] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=4

[ 0.009249] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.009268] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.009278] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.010077] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.010126] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=0 transferred=16

[ 0.010138] [00000c5b] libusbx: debug [handle_control_completion] handling completion status 0

[ 0.010149] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.010162] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x16681f8 has callback 0x7fbb5a5c97f0

[ 0.010172] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=16

Product: "MSM8x60"

length: 18

device class: 2

S/N: 0

VID:PID: 04E8:685D

bcdDevice: 0100

iMan:iProd:iSer: 1:2:0

nb confs: 1

[ 0.010239] [00000c5b] libusbx: debug [libusb_get_config_descriptor] index 0

interface[0].altsetting[0]: num endpoints = 1

Class.SubClass.Protocol: 02.02.01

endpoint[0].address: 82

max packet size: 0010

polling interval: 09

interface[1].altsetting[0]: num endpoints = 2

Class.SubClass.Protocol: 0A.00.00

endpoint[0].address: 81

max packet size: 0200

polling interval: 00

endpoint[1].address: 01

max packet size: 0200

polling interval: 00

Claiming interface...

[ 0.010341] [00000c5b] libusbx: debug [libusb_claim_interface] interface 1

Setting up interface...

[ 0.010389] [00000c5b] libusbx: debug [libusb_set_interface_alt_setting] interface 1 altsetting 0

Initialising protocol...

[ 0.013097] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.013156] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.013185] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.013858] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.013932] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=-32 transferred=0

[ 0.013962] [00000c5b] libusbx: debug [handle_control_completion] handling completion status -32

[ 0.013990] [00000c5b] libusbx: debug [handle_control_completion] unsupported control request

[ 0.014019] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.014048] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x1668288 has callback 0x7fbb5a5c97f0

[ 0.014077] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=0

WARNING: Control transfer #1 failed. Result: -9

WARNING: Control transfer #1 failed. Result: 0

[ 0.014209] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.014253] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.014282] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.014857] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.014933] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=-32 transferred=0

[ 0.014962] [00000c5b] libusbx: debug [handle_control_completion] handling completion status -32

[ 0.014990] [00000c5b] libusbx: debug [handle_control_completion] unsupported control request

[ 0.015019] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.015049] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x1668288 has callback 0x7fbb5a5c97f0

[ 0.015077] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=0

WARNING: Control transfer #2 failed. Result: -9

WARNING: Control transfer #2 failed. Result: 0

[ 0.015185] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.015229] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.015258] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.015785] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.015860] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=-32 transferred=0

[ 0.015889] [00000c5b] libusbx: debug [handle_control_completion] handling completion status -32

[ 0.015918] [00000c5b] libusbx: debug [handle_control_completion] unsupported control request

[ 0.015946] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.015976] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x1668288 has callback 0x7fbb5a5c97f0

[ 0.016014] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=0

WARNING: Control transfer #3 failed. Result: -9

WARNING: Control transfer #3 failed. Result: 0

[ 0.016134] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.016178] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.016207] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.016765] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.016858] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=-32 transferred=0

[ 0.016887] [00000c5b] libusbx: debug [handle_control_completion] handling completion status -32

[ 0.016916] [00000c5b] libusbx: debug [handle_control_completion] unsupported control request

[ 0.016944] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.016974] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x1668288 has callback 0x7fbb5a5c97f0

[ 0.017001] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=0

WARNING: Control transfer #4 failed. Result: -9

WARNING: Control transfer #4 failed. Result: 0

[ 0.017105] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.017150] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.017179] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.017769] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.017846] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=-32 transferred=0

[ 0.017874] [00000c5b] libusbx: debug [handle_control_completion] handling completion status -32

[ 0.017903] [00000c5b] libusbx: debug [handle_control_completion] unsupported control request

[ 0.017931] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.017961] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x1668288 has callback 0x7fbb5a5c97f0

[ 0.017988] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=0

WARNING: Control transfer #5 failed. Result: -9

WARNING: Control transfer #5 failed. Result: 0

[ 0.018092] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.018137] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.018165] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 0.018648] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 0.018731] [00000c5b] libusbx: debug [reap_for_handle] urb type=2 status=-32 transferred=0

[ 0.018766] [00000c5b] libusbx: debug [handle_control_completion] handling completion status -32

[ 0.018801] [00000c5b] libusbx: debug [handle_control_completion] unsupported control request

[ 0.018836] [00000c5b] libusbx: debug [disarm_timerfd]

[ 0.018872] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x1668288 has callback 0x7fbb5a5c97f0

[ 0.018901] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=0

WARNING: Control transfer #6 failed. Result: -9

WARNING: Control transfer #6 failed. Result: 0

[ 0.019008] [00000c5b] libusbx: debug [add_to_flying_list] arm timerfd for timeout in 1000ms (first in line)

[ 0.019037] [00000c5b] libusbx: debug [submit_bulk_transfer] need 1 urbs for new transfer with length 4

[ 0.019084] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 0.019112] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 1.019126] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 1.019166] [00000c5b] libusbx: debug [handle_events] timerfd triggered

[ 1.019177] [00000c5b] libusbx: debug [libusb_cancel_transfer]

[ 1.019365] [00000c5b] libusbx: debug [disarm_timerfd]

[ 1.019411] [00000c5b] libusbx: debug [libusb_handle_events_timeout_completed] doing our own event handling

[ 1.019425] [00000c5b] libusbx: debug [handle_events] poll() 4 fds with timeout in 60000ms

[ 1.019445] [00000c5b] libusbx: debug [handle_events] poll() returned 1

[ 1.019464] [00000c5b] libusbx: debug [reap_for_handle] urb type=3 status=-2 transferred=0

[ 1.019477] [00000c5b] libusbx: debug [handle_bulk_completion] handling completion status -2 of bulk urb 1/1

[ 1.019490] [00000c5b] libusbx: debug [handle_bulk_completion] abnormal reap: urb status -2

[ 1.019501] [00000c5b] libusbx: debug [handle_bulk_completion] abnormal reap: last URB handled, reporting

[ 1.019511] [00000c5b] libusbx: debug [usbi_handle_transfer_cancellation] detected timeout cancellation

[ 1.019520] [00000c5b] libusbx: debug [disarm_timerfd]

[ 1.019531] [00000c5b] libusbx: debug [usbi_handle_transfer_completion] transfer 0x1668288 has callback 0x7fbb5a5c97f0

[ 1.019540] [00000c5b] libusbx: debug [sync_transfer_cb] actual_length=0

ERROR: Failed to send data: "ODIN"

ERROR: Failed to send data: "(null)"

Releasing device interface...

[ 1.019581] [00000c5b] libusbx: debug [libusb_release_interface] interface 1

[ 1.019618] [00000c5b] libusbx: debug [libusb_close]

[ 1.019640] [00000c5b] libusbx: debug [usbi_remove_pollfd] remove fd 11

[ 1.019679] [00000c5b] libusbx: debug [libusb_exit]

[ 1.019689] [00000c5b] libusbx: debug [libusb_exit] destroying default context​

Will this help to find out whether emmc memory is dead?