I have recently updated my JP-8000 to the 1.05 firmware and think that I can help a bit.
First off to access info on the JP-8000 on Rolands site just type "JP-8000" into their search bar or go here: http://www.rolandus.com/products/produc ... jectId=261
The first thing that I want to say is that Juno106 is sort of right in what he asked. If there is nothing wrong with the version you have then don't update the firmware. With each version they change some of the sounds and the RPS loops. I LOVED the RPS on version 1.04 but it is horrible on 1.05. Roland only has 1.05 available, even through the tech support. I have talked to them and due to "Legal" issues they can not continue to support the previous firmware versions.
My firmware update to 1.05 did not work the first 2 times I tried it. I had the same screen problem as SCION7000 when I tried to reboot it. I realized that the update software that roland supplies was sending all of the midi files in a row to the JP-8000. It does not work that way. You have to separate the files into their own folders and send them one by one. Each time you send one you have to complete the transfer on the JP-8000. You also have to reset the pitch and modulation controls.
TO UPDATE I USED:
UPD SMF Update Application (From Roland's Website)
M-Audio Uno USB to MIDI Adapter (You can get these at most Guitar Centers for about $30)
HERE IS THE UPDATE PROCEDURE AND CHECKSUM FOR 1.05:
1) Connect the sequencer MIDI-OUT to the JP-8000 MIDI-IN.
2) Turn on the power of the JP-8000 while holding down the [LFO1 WAVEFORM],
[OSC1 WAVEFORM], [OSC2 SYNC] and [OSC2 WAVEFORM] buttons.
3) Press REC.
4) When 'Ready to update' appears on the screen, send the first file (_00001.mid)
from your sequencer.
5) When the file is completed, verify that the checksum is indicated as below.
Block1 ( chksum = 49F8 ) => filename : '_00001.mid'.
Block2 ( chksum = 12E3 ) => filename : '_00002.mid'.
Block3 ( chksum = A146 ) => filename : '_00003.mid'.
Block4 ( chksum = E6EB ) => filename : '_00004.mid'.
Block5 ( chksum = 5455 ) => filename : '_00005.mid'.
Block6 ( chksum = 672D ) => filename : '_00006.mid'.
Block7 ( chksum = C131 ) => filename : '_00007.mid'.
Block8 ( chksum = F294 ) => filename : '_00008.mid'.
If the value is different, press [EXIT] and repeat steps 4 and 5.
6) If the value is correct, press the [REC] button.
7) Load the files one at a time, in sequence _00002.mid to _00008.mid and repeat
8 ) One all the files have been loaded, 'Completed' will be indicated on the screen.
Turn off the power of the JP-8000.
Reset Pitch Bender and Ribbon Controller Procedure:
1) Turn on power while holding [OSC2 SYNC], [-12dB/-24dB] and [FILTER TYPE] to enter Test Mode. Wait until display
indicates " MIDI Test."
2) Press the  button to display " Bend Mod."
3) Push the bender lever left fully and gradually return it to the center. Press [LOWER].
4) Push the bender lever right fully and gradually return it to the center. Press [UPPER].
5) Push the bender lever to the MOD position and then gradually return it to the original position. Press [KEY MODE].
6) When the '*' appears on the display, press [UP].
7) From the previous display, press  to display " Ribbon."
8 ) While pressing down on the left edge of the ribbon controller, press [LOWER].
9) While pressing down on the right edge of the ribbon controller, press [UPPER].
10) While pressing down on the center of the ribbon controller, press [KEY MODE].
11) When the '*' appears on the display, press [UP].
12) Turn off the power of the JP-8000.
Use the following procedure to reset the JP-8000 to factory settings:
1) Turn on the power of the JP-8000. The unit may display "Memory Damaged."
2) While holding [SHIFT], press [INIT/UTIL].
3) Press [INIT/UTIL] repeatedly to select "INITIALIZE WRITE."
4) Use the [UP / DOWN] buttons to select "FACTORY PRESET," then press [WRITE].
After this procedure has been completed, the new version of software should be ready to go.
SCION7000, I would suggest just trying the factory setting reset on the one with the bad display and see if you can get it back up. Then worry about the firmware.
With all of this said, I recently met someone that supposedly has all of the past firmware versions for the JP-8000 as he has owned a few of them over the years. He said that he would gladly dig them out and get them to me so I can restore my JP-8000 to the 1.04 version. I will try my best to get them online soon and post a link.
If you have any questions let me know. Hope this helps.