I know I am writing that a LONG time after this was more or less resolved, for future reference for anyone that has issues updating firmware for Samson Graphite or Carbon, no matter which size. They are not very clear about one HUGE thing that you must do to update the firmware properly. I was having the blank LCD screen issue, and the PRESET and then keypad 1, then enter to reset to factory settings was not working for me. I realized, you can either use the buttons up near the MAIN button, but also the actual keys themselves have the needed functions labelled above the keys. For fixing it using the keys, you have to press PRESET, then Key 1 (furthest left key), then enter on the actual keyboard keys. Sometimes, the other buttons responded, sometimes they didn't. The fix if the screen is blank and the device is not responding to the reset or detecting as a MIDI device. Quick disclaimer, I was unable to get this to work on Windows 10, but it worked in OS X. I also switched out cables when it worked on OS X, so I am not ruling out that this will work on Windows.
TL/DR - Fix if LCD screen is blank, or cannot update firmware:
1) Download newest firmware from Samson website
http://www.samsontech.com/samson/produc ... ntrollers/
2) Download newest version of the firmware update tool, not the samson editor, the following does not work with the editor from my experience.
3) Install firmware update utility
4) Boot computer with midi keyboard powered on, even if LCD screen isn't showing.
5) Open Firmware update utility
6) "Open File" and select the .bin file of the new firmware
7) This is the KEY part that is not in the manual, Power the keyboard off while still having the USB plugged in, then HOLD down both the - and + transpose buttons while it's powered off

Turn the keyboard on while holding BOTH transpose buttons until it displays either "UPD" on the carbon series, I believe, or on mine (Graphite 49) it simply displayed the firmware version on the LCD screen.
9) The updater utility displays "looking for midi device" or something similar to that, if you get a response and are able to click "update and it works for you from this point on, great! If not...
10) Reload the .bin file by clicking "Open File" again, and then click "Update", this worked in my case.
11) I cannot recall if I powered the keyboard down and then back up while holding both transpose buttons, but if it still is not updating for you at this point, it's worth a try.
Hope this helps solve some headaches, as this was HOURS of research to get this working.