<thread update>
Now bootlooping so need to actually fix the Ubuntu issue.
So I figured out a trick to sometimes enter a state where flasher could upload firmware by booting or rebooting.
For some reason the FIASCO .bin was not uploading and I would boot up to no graphics and no fonts but the QT buttons were present, the last time it loaded to 47% now I am boot looped
any ideas would be appreciated,see the saga below if you like
I suspect the rejection by Ubuntu of the connection has something to do with missing /proc/bus/usb I tried the patch since mounting it didnt work, still nothing, and why it would flash sometimes if that were the issue?
Also tried with a WInXP SP-3 laptop, drivers load and unload instantly.
</update>
Problems flashing a used N900 off of ebay that can usualy connect as bulk storage and transfer files properly. FWIW I seem to be unable to use H-E-N and several other apps which is a major reason that I want to flash the phone and start clean, I cant even go back to the Nokia kernel from PK50.

Anyways this is the output of /var/log/syslog (the new /var/log/messages) from Ubuntu 12 when I plug the unpowered phone to USB with the U pressed, for some reason the N900 is getting rejected.

May 21 14:34:40 suter-AO722 kernel: [17324.540368] usb 1-1: new high-speed USB device number 5 using ehci_hcd
May 21 14:34:40 suter-AO722 kernel: [17324.672988] usb 1-1: unable to get BOS descriptor
May 21 14:34:40 suter-AO722 mtp-probe: checking bus 1, device 5: "/sys/devices/pci0000:00/0000:00:12.2/usb1/1-1"
May 21 14:34:40 suter-AO722 mtp-probe: bus: 1, device: 5 was not an MTP device
May 21 14:34:40 suter-AO722 kernel: [17324.975334] usb 1-1: USB disconnect, device number 5

so I temporarily add cdc_phonet to the blacklist per though tat doesn't seem to be a problem
http://talk.maemo.org/showthread.php?t=49256 and
http://forums.internettablettalk.com...00&postcount=2
http://wiki.maemo.org/Updating_the_tablet_firmware

The below represents several trys plugging and unplugging, the best results when I would connect all of the cables and hold U key as I inserted the battery to the N900. I only once got the SDA and SDB loading as SCSI drives

suter@suter-AO722:/etc/modprobe.d$ sudo tail -f /var/log/syslog
May 21 14:45:32 suter-AO722 kernel: [17976.571326] usb 3-1: unable to get BOS descriptor
May 21 14:45:32 suter-AO722 kernel: [17976.573329] usb 3-1: not running at top speed; connect to a high speed hub
May 21 14:45:32 suter-AO722 mtp-probe: checking bus 3, device 2: "/sys/devices/pci0000:00/0000:00:12.0/usb3/3-1"
May 21 14:45:32 suter-AO722 mtp-probe: bus: 3, device: 2 was not an MTP device
May 21 14:45:32 suter-AO722 kernel: [17976.884752] usb 3-1: USB disconnect, device number 2
May 21 14:57:07 suter-AO722 kernel: [18671.736367] usb 1-2: new high-speed USB device number 7 using ehci_hcd
May 21 14:57:07 suter-AO722 kernel: [18671.869622] usb 1-2: unable to get BOS descriptor
May 21 14:57:07 suter-AO722 mtp-probe: checking bus 1, device 7: "/sys/devices/pci0000:00/0000:00:12.2/usb1/1-2"
May 21 14:57:07 suter-AO722 mtp-probe: bus: 1, device: 7 was not an MTP device
May 21 14:57:08 suter-AO722 kernel: [18672.171529] usb 1-2: USB disconnect, device number 7
May 21 15:09:35 suter-AO722 kernel: [19419.596370] usb 1-1: new high-speed USB device number 8 using ehci_hcd
May 21 15:09:35 suter-AO722 kernel: [19419.729501] usb 1-1: unable to get BOS descriptor
May 21 15:09:35 suter-AO722 mtp-probe: checking bus 1, device 8: "/sys/devices/pci0000:00/0000:00:12.2/usb1/1-1"
May 21 15:09:35 suter-AO722 mtp-probe: bus: 1, device: 8 was not an MTP device
May 21 15:09:35 suter-AO722 kernel: [19420.031664] usb 1-1: USB disconnect, device number 8
May 21 15:09:47 suter-AO722 kernel: [19431.848369] usb 1-1: new high-speed USB device number 9 using ehci_hcd
May 21 15:09:47 suter-AO722 kernel: [19431.985221] scsi2 : usb-storage 1-1:1.0
May 21 15:09:47 suter-AO722 mtp-probe: checking bus 1, device 9: "/sys/devices/pci0000:00/0000:00:12.2/usb1/1-1"
May 21 15:09:47 suter-AO722 mtp-probe: bus: 1, device: 9 was not an MTP device
May 21 15:09:48 suter-AO722 kernel: [19432.986341] scsi 2:0:0:0: Direct-Access Nokia N900 031 PQ: 0 ANSI: 2
May 21 15:09:48 suter-AO722 kernel: [19432.987059] scsi 2:0:0:1: Direct-Access Nokia N900 031 PQ: 0 ANSI: 2
May 21 15:09:48 suter-AO722 kernel: [19432.989909] sd 2:0:0:0: Attached scsi generic sg1 type 0
May 21 15:09:48 suter-AO722 kernel: [19432.993121] sd 2:0:0:1: Attached scsi generic sg2 type 0
May 21 15:09:48 suter-AO722 kernel: [19432.996963] sd 2:0:0:1: [sdc] Attached SCSI removable disk
May 21 15:09:48 suter-AO722 kernel: [19432.999070] sd 2:0:0:0: [sdb] Attached SCSI removable disk

but this is what flasher3.5 says even after I saw the SCSI drivers load(that is the only time I have gotten SCSI)

Image 'mmc', size 255947 kB
Version RX-51_2009SE_10.2010.13-2.VANILLA
Suitable USB device not found, waiting.

Nothing beyond that

I am not sure what output I should be seeing in /var/log/syslog when the N900 is causing the correct driver to load. I dont know if this is a problem with the N900 or with the Ubuntu any USB gurus have ideas.

So I finally got flasher to go while watching /var/log/syslog and booting up trying to figure out what was wrong with USB. I booted up with the N900 USB cable inserted, shut down with the flasher running and SURPRISE! the flasher suddenly starts running.
So when the phone boots there is no graphics and while I get working buttons for things like shut down they are filled with the rectangles you see when your browser doesn't recognise a font. I try again to flash... Same no luck. I wonder what the trick was the one go?

so this is what I saw when I was able to get flasher to run.
May 21 16:28:49 suter-AO722 kernel: [24174.077446] usb 1-1: USB disconnect, device number 23
May 21 16:28:53 suter-AO722 kernel: [24177.932380] usb 1-1: new high-speed USB device number 24 using ehci_hcd
May 21 16:28:53 suter-AO722 mtp-probe: checking bus 1, device 24: "/sys/devices/pci0000:00/0000:00:12.2/usb1/1-1"
May 21 16:28:53 suter-AO722 mtp-probe: bus: 1, device: 24 was not an MTP device
May 21 16:28:56 suter-AO722 kernel: [24180.394672] usb 1-1: usbfs: process 3963 (flasher-3.5) did not claim interface 2 before use
May 21 16:31:01 suter-AO722 kernel: [24305.389414] usb 1-1: USB disconnect, device number 24

I am not a USB guru but I am thinking that some package or driver on Ubuntu is overriding and kicking out the flash mode USB connect of the N900, I cant find it documented though.
If I plug in the N900 offline on USB without the U pressed I get it connecting as two partitions, so the first post's instance of bulk storage is explained.

May 21 19:27:48 suter-AO722 kernel: [ 3576.152187] usb 1-1: new high-speed USB device number 25 using ehci_hcd
May 21 19:27:48 suter-AO722 kernel: [ 3576.285792] usb 1-1: unable to get BOS descriptor
May 21 19:27:48 suter-AO722 mtp-probe: checking bus 1, device 25: "/sys/devices/pci0000:00/0000:00:12.2/usb1/1-1"
May 21 19:27:48 suter-AO722 mtp-probe: bus: 1, device: 25 was not an MTP device
May 21 19:27:48 suter-AO722 kernel: [ 3576.589047] usb 1-1: USB disconnect, device number 25

<edit, I think this is the correct solution now that I am boot looped and need to connect without tricks>
So this is a cut/paste from the wiki flashing page, is this what I am missing? If so how does one mount USBFS when the flash mode USB connection gets kicked out so quickly?

USB

It may help to connect directly to the computer USB ports, avoiding the use of a hub - which includes the USB ports on laptop docking stations. The USB ports in the back of a laptop may also be better than using those in the front.

Some distributions do not present the USB device in the way that it expects it. First, see if it is necessary to "mount" USB:

mount -t usbfs usbfs /proc/bus/usb

If that does not work, try patching the flasher code. This replaces the use of /proc/bus/usb with the newer /dev/bus/usb filesystem:

perl -pi -e 's-/proc/bus/usb-/dev/bus/usb\000-;' -i.backup $FLASHER

Replace $FLASHER with the path to your flasher-2.0 or flasher-3.0 Linux binary.

So I somehow got the flasher to go again, with much mysterious strangeness, this time by booting the phone with the USB cable attached.
Loaded EMMC first then FIASCO.
I was using the latest international FIASCO, very appropriate name, I again have the phone booting to no graphics and no fonts.....
This is what it looked like flashing, is there anything wrong here?

suter@suter-AO722:~/Desktop/flashN900$ sudo flasher-3.5 -F RX-51_2009SE_10.2010.13-2.VANILLA_PR_EMMC_MR0_ARM.bin -f
flasher v2.5.2 (Oct 21 2009)

Image 'mmc', size 255947 kB
Version RX-51_2009SE_10.2010.13-2.VANILLA
Suitable USB device not found, waiting.
USB device found found at bus 001, device address 024.
Using flashing protocol Mk II.
SU_VERIFY_COMMS_REQ timed out.
suter@suter-AO722:~/Desktop/flashN900$ sudo flasher-3.5 -F RX-51_2009SE_10.2010.13-2.VANILLA_PR_EMMC_MR0_ARM.bin -f
[sudo] password for suter:
flasher v2.5.2 (Oct 21 2009)

Image 'mmc', size 255947 kB
Version RX-51_2009SE_10.2010.13-2.VANILLA
Suitable USB device not found, waiting.
USB device found found at bus 001, device address 028.
Found device RX-51, hardware revision 2101
NOLO version 1.4.14
Version of 'sw-release': RX-51_2009SE_21.2011.38-1_PR_MR0
Booting device into flash mode.
Suitable USB device not found, waiting.
USB device found found at bus 001, device address 029.
Raw data transfer EP found at EP2.
Image(s) flashed successfully in 28.467 s (8990 kB/s)!
suter@suter-AO722:~/Desktop/flashN900$ sudo flasher-3.5 -F RX-51_2009SE_ -f RX-51_2009SE_10.2010.13-2.VANILLA_PR_EMMC_MR0_ARM.bin
RX-51_2009SE_20.2010.36-2_PR_COMBINED_MR0_ARM.bin
suter@suter-AO722:~/Desktop/flashN900$ sudo flasher-3.5 -F RX-51_2009SE_20.2010.36-2_PR_COMBINED_MR0_ARM.bin -f
flasher v2.5.2 (Oct 21 2009)

SW version in image: RX-51_2009SE_20.2010.36-2_PR_MR0
Image 'kernel', size 1705 kB
Version 2.6.28-20103103+0m5
Image 'rootfs', size 185728 kB
Version RX-51_2009SE_20.2010.36-2_PR_MR0
Image 'cmt-2nd', size 81408 bytes
Version BB5_09.36
Image 'cmt-algo', size 519808 bytes
Version BB5_09.36
Image 'cmt-mcusw', size 5826 kB
Version rx51_ICPR82_10w08
Image '2nd', size 14720 bytes
Valid for RX-51: 2217, 2218, 2219, 2220, 2120
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2217, 2218, 2219, 2220, 2120
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2217, 2218, 2219, 2220, 2120
Version 1.4.14.9+0m5
Image '2nd', size 14720 bytes
Valid for RX-51: 2101, 2102, 2103
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2101, 2102, 2103
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2101, 2102, 2103
Version 1.4.14.9+0m5
Image '2nd', size 14848 bytes
Valid for RX-51: 2307, 2308, 2309, 2310
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2307, 2308, 2309, 2310
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2307, 2308, 2309, 2310
Version 1.4.14.9+0m5
Image '2nd', size 14848 bytes
Valid for RX-51: 2407, 2408, 2409, 2410
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2407, 2408, 2409, 2410
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2407, 2408, 2409, 2410
Version 1.4.14.9+0m5
Image '2nd', size 14848 bytes
Valid for RX-51: 2301, 2302, 2303, 2304, 2305, 2306
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2301, 2302, 2303, 2304, 2305, 2306
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2301, 2302, 2303, 2304, 2305, 2306
Version 1.4.14.9+0m5
Image '2nd', size 14848 bytes
Valid for RX-51: 2401, 2402, 2403, 2404, 2405, 2406
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2401, 2402, 2403, 2404, 2405, 2406
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2401, 2402, 2403, 2404, 2405, 2406
Version 1.4.14.9+0m5
Image '2nd', size 14720 bytes
Valid for RX-51: 2104, 2105, 2106, 2107, 2108, 2109, 2110, 2111, 2112, 2113, 2114, 2115, 2116, 2117, 2118, 2119
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2104, 2105, 2106, 2107, 2108, 2109, 2110, 2111, 2112, 2113, 2114, 2115, 2116, 2117, 2118, 2119
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2104, 2105, 2106, 2107, 2108, 2109, 2110, 2111, 2112, 2113, 2114, 2115, 2116, 2117, 2118, 2119
Version 1.4.14.9+0m5
Image '2nd', size 14848 bytes
Valid for RX-51: 2501, 2502, 2503, 2504, 2505, 2506
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2501, 2502, 2503, 2504, 2505, 2506
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2501, 2502, 2503, 2504, 2505, 2506
Version 1.4.14.9+0m5
Image '2nd', size 14848 bytes
Valid for RX-51: 2607, 2608, 2609, 2610
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2607, 2608, 2609, 2610
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2607, 2608, 2609, 2610
Version 1.4.14.9+0m5
Image '2nd', size 14848 bytes
Valid for RX-51: 2507, 2508, 2509, 2510
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2507, 2508, 2509, 2510
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2507, 2508, 2509, 2510
Version 1.4.14.9+0m5
Image '2nd', size 14720 bytes
Valid for RX-51: 2201, 2202, 2203, 2204, 2205, 2206, 2207, 2208, 2209, 2210, 2211, 2212, 2213, 2214, 2215, 2216
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2201, 2202, 2203, 2204, 2205, 2206, 2207, 2208, 2209, 2210, 2211, 2212, 2213, 2214, 2215, 2216
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2201, 2202, 2203, 2204, 2205, 2206, 2207, 2208, 2209, 2210, 2211, 2212, 2213, 2214, 2215, 2216
Version 1.4.14.9+0m5
Image '2nd', size 14848 bytes
Valid for RX-51: 2601, 2602, 2603, 2604, 2605, 2606
Version 1.4.14.9+0m5
Image 'xloader', size 14848 bytes
Valid for RX-51: 2601, 2602, 2603, 2604, 2605, 2606
Version 1.4.14.9+0m5
Image 'secondary', size 109440 bytes
Valid for RX-51: 2601, 2602, 2603, 2604, 2605, 2606
Version 1.4.14.9+0m5
USB device found found at bus 001, device address 029.
Raw data transfer EP found at EP2.
Using flashing protocol Mk II.

Considering how longthe N900 takes to laod the FIASCO vs the EMMC I am suspecting it is not loading at all.
I got the N900 to flashagain by watching /var/log/syslog and while the flasher was running pluggin the off phoneinto USB,the SCSIdiscs showed up and I unplugged and immediatly replugged the phone.
I suspect a but of chance is involved and the trick is to just keep trying.
As I write this post...
The phone is now booting for the first time after flash and SURPRISE! no fonts,no graphics except the dialog buttons with the not found font rectangles , the FIASCO flash didnt load anything at all!
Any Ideas?

What happens if I flash the FIASCO but leave the apparently fine EMMC?

I tried Fiasco agin,managed to get a flash quickly and got a failed uploadat 47%.

USB device found found at bus 001, device address 057.
Found device RX-51, hardware revision 2101
NOLO version 1.4.14
Version of 'sw-release': RX-51_2009SE_21.2011.38-1_PR_MR0
Sending xloader image (14 kB)...
100% (14 of 14 kB, avg. 3625 kB/s)
Sending secondary image (106 kB)...
100% (106 of 106 kB, avg. 10687 kB/s)
Flashing bootloader... done.
Sending cmt-2nd image (79 kB)...
100% (79 of 79 kB, avg. 11357 kB/s)
Sending cmt-algo image (507 kB)...
100% (507 of 507 kB, avg. 23073 kB/s)
Sending cmt-mcusw image (5826 kB)...
100% (5826 of 5826 kB, avg. 23589 kB/s)
Flashing cmt-mcusw... done.
Sending kernel image (1705 kB)...
100% (1705 of 1705 kB, avg. 17768 kB/s)
Flashing kernel... done.
Sending and flashing rootfs image (185856 kB)...
47% (88064 of 185856 kB, 12748 kB/s)
Write failed after 90177536 bytes
usb_bulk_write: No such device

Now whenI go to boot all I get is the NOKIA screen and the white booting light for about 10 sec. Horay for brickoramma!

So how to recover form a boot looped phone that would only enter flash mode related to entering booting or rebooting?
I still dont know why Ubuntu kicks out the connection.

I re-read http://discussions.europe.nokia.com/.../589603/page/4

this is a problem but the solution given doesnt work

/proc/bus/usb
df: `/proc/bus/usb': No such file or directory
df: no file systems processed

sudo mount -t usbfs usbfs /proc/bus/usb
[sudo] password for suter:
mount: mount point /proc/bus/usb does not exist

so I look in /proc/bus and there is an input and pci directory but no usb...

No idea how to fix that issue, and no help in the flash wiki page.

Borrowed a Win-XP laptop and made sure it was up to date on updates(sp-3).
When I first plugged the N900 in I got prompts for drivers for Nokia ROM or for "N900 Phone Parent" if I do the boot with U pressed.
Once I have the drivers loaded from the windows flasher installer and then plug in the N900 with or without the U pressed it does the Windows driver loading da-ding sound and then a driver unloading ding-dong in quick sucession, so quick that the sounds are on top of each other I gives no pop up in the systray. I do get a warning that a problem occurred during installation. Your new hardware might not work properly, no warning just the pop in/out of the WinXP driver sounds.
WTF is going on here, I can accept that there is wierdness in Ubuntu but I saw stuff trying to load properly in XP until I had added drivers.

Just curious is this a unique issue that nobody has ever experienced?
Is my N900 special in a bad way that windows and ubuntu both kick the connection out instantly?
Is anyone bothering to read this giant wall of log dumps and text?
I seem to be finding my posts here now in my google searches on the top so it might be unique.
thanks to those that do.
bigger thanks for what I assume is a simple solution that I am missing.