USB flash memory not detected on startup

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Guest

Im having a problem where I cant get USB flash discs to be consistenty
detected on start up.
Im using XPe Sp2 and a number of different makes of USB stick but they are
regularly not detected properly when the PC powers up, the Device manager
says that they are "Unknown Device" so I cannot access the files on the stick
until it is reinserted in the PC.

Does anyone have a fix for this or know what causes it.
 
Dominic,

Do you know how the same brand USB stick works with XP Pro? Does it also expose the problem?

One possible explanation...

Unfortunately, many USB mass storage device manufacturers do not follow properly protocols (USB MSC, SCSI2) while implementing their
device firmware.
XP itself has some fixes for some known devices but sometimes timing issues may be seen with some brands.
Since the XPe image you got there is not the same as XP Pro, booting time is different and etc., it may effect when controller
driver gets initialize and USB stack fires up. While the device is being plugged in before the boot, it may appear to not be working
(stalled or etc.) later.
 
It does seem to work on Windows XP Pro, it is only XPe that it doesnt.
I have a batch of sticks that are all the same type from the same
manufacturer and 50% will work and 50% wont, when a stick is found not to
work it wont ever work, maybe a different version of Firmware?

But is there a way to get an app. such as devcon.exe to resolve this issue
by rebuilding the USB stacks?
 
Dominic,

I don't know a good way to fix your issue unless you develop your own USB drivers.

You can try simpler trick though. Disable USB controlller driver, reboot and after Shell is up a running try to enable back the
driver. See if this helps.
 
Hi Dominic,

I saw a similar behavior of Windows Embedded SP1.

I can boot a generic XPE image from a SanDisk micro cruzer USB stick
(512MB).

The same image on simply another USB stick which "exact" the same
SanDisk micro cruzer
gives BSOD 0x7B.
So I believe Konstantin, that XPE is vulnerable if something happens
with the device firmware, that you dont know.

With real XP Pro, these two USB sticks works wonderfull also for USB
boot.

Nice to hear from you
Dietmar
 
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