how to modify serial number of usb device by usb filter driver?

hi, I want to modify the serial number or PID/VID of my usb mass stroage disk.
I try it by an usb class filter driver to capture the
URB_FUNCTION_GET_DESCRIPTOR_FROM_DEVICE,then modify the data...
But,It seems useless!
how should I do? many thanks!

 

what side affect do you want your change to have? that the usb core not use
it for a unique ID or that usbstor uses your changed value ?

d

 

Thanks for your answer!
Infect, I have two usb device with the same pid/vid and serial number.
them can not co-exist in windows...
for certain reason,I have to fix the bug by modify somthing inside os..
I think I should change the string of iSerialNumber before os load
usbstor.sys.
so,the changed value should be used by usb core or even lower drivers.
right?
but I don't know how to do that!

 

Add the filter which will just ignore the serial number by patching the
DEVICE_CAPABILITIES and resetting UniqueId bit.

--
Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation

http://www.storagecraft.com

 

that is too late. you need to filter the parent hub's query device
relations. you need to filter the entire usb bus since you don't know which
port you will be attached to. this is a very difficult task, you can't
really work around your broken hw this way

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You are right...I had just follow the advice by Maxim S. Shatskih.
it still can't work

I will try to filter the entire bus...any advice?
or, Is there other way to make the two device work together?

 

By the way, the two devices (with identical pid/vid and serial number) work
well in Win XP, but not in Win 2k.
what's the difference?

 

the XP usb core tracks serial numbers and does not use the serial number as
a unique identifier on the bus

d

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you are proposing to write a bus filter driver. quite difficult to do and
completely undocumented and unsupported by microsoft.

d

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So this is a bug in win2000, fixed later. They're making progress

There are some registry hacks - IgnoreHWSerNum, GlobalDisableSerNumGen.
See:
http://www.usb.org/phpbb/viewtopic.php?p=26740&sid=af2c39585b63510bba1f3559af8282b4

Regards,
--PA

 

To be completely fair, it's a bug in the devices that have non-unique
serial numbers. That's a violation of the USB spec. USB devices are very
clearly required to either have unique serial numbers or no serial
numbers at all.

 

Yep. But, as saying goes - In specifications, Murphy's Law supersedes Ohm's,
in this case it supersedes the USB spec

--PA

 

...My device has a bug! it violate the spec.
But how to give each device a unique ID?
the id is stored inside eprom,so each device has a same initial id before
assign an unique one by configuraton tool...the question is how to
configure multiple devices at a time?

a working method is,while enumerate devices,reset iSerialNumber field of
device descriptor by firmware...so the UniqueId field return zero while
query device capabilites.
but,it's also violate the spec...right?

 

thanks a lot...the utility is important to me!!

 

There are 2 typical techniques:

1) Program the serial numbers uniquely in the first place when you burn
the firmware into the EEPROM.

2) Program the device with a null serial number descriptor (i.e. the
device says it doesn't have a serial number, which is legal according to
the spec) and then program the unique serial number over that later.
This requires a certain amount of cleverness because it involves leaving
enough space to overwrite the descriptor from that point onward, but it
is a solution for people that can't manufacture them right in the first
place.

3) Actually, there's a third technique that people use, but that's
already been mentioned: program them with non-unique serial numbers and
then turn off serial number checking on your functional test machine and
reprogram them. That way, the bug only exists inside your factory, and I
doubt the USB-IF would object to that .