ULi M920x firmware
You can obtain an M920x firmware in a two step process by, first, running your device natively under Windows and using either usbsnoop or SnoopyPro, or, alternatively, under Linux using a combination of usbmon and vmware player running a Windows client (described further in this thread). The second step involves parsing the actual firmware code out of the data captured in the first step of the process (this is necessary regardless of which of the particular methods listed above was used).
Introduction
Under a Windows environment, as soon as you plug your M920x based device into an USB port, the M920x firmware will be sent, so you should not be trying to have any other program be starting at the same time in the background. In addition, during Windows driver installation, those device's that shipped with a remote controller might have setup a background process, called Uremote.exe (or similar). If you find such an installed program running, please shut it down so that it doesn't cause traffic in the logs.
M920x firmware consists of a number of 64 byte long USB control messages. After these control messages you will see another control message with request, value, index of M9206_CORE(0x22), 0x01, M9206_FW_GO(0xff69), respectively.
After the USB device receives this message, it will disconnect itself from the bus and appear again with (possibly) different idVendor and idProduct. These new ids are known as warm ids. At very least you will see your device having new endpoints that will be used to transmit data.
It's important to have Usbsnoop or Snoopypro installed and logging before you plug in the device. It might take several attempts to get a dump of the initial bus traffic where this firmware is visible.
After acquiring a log with firmware, you will need to process it with various tools.
usbsnoop
First with parser.pl and then with M920x parse (arguments -i us -m fw)
SnoopyPro
M920x sp firmware can only read data in this format: http://www.roback.cc/projects/iRiver/howto/snoopypro/wordpad_saved.png
usbmon
Recompile your kernel with CONFIG_USB_DEVICEFS, CONFIG_USB_MON and CONFIG_DEBUG_FS selected in your kernel config. Then patch linux/drivers/usb/mon/mon_text.c with http://www.rasterburn.org/~aet/m920x/usbmon_ext.diff. Finally make sure that CONFIG_USB_EHCI_HCD is set to m and not y. After rebooting your new kernel, install vmware player and get everything ready on that front. See http://software.newsforge.com/article.pl?sid=06/05/16/1940214 for more details on this.
You will probably need these: (look up with google if interested)
# remove usb 2.0 support. vmware might freak out your computer otherwise rmmod ehci_hcd mount -t debugfs none_debugs /sys/kernel/debug modprobe usbmon mount -t usbfs none /proc/bus/usb # needed by vmware chmod -R a+rw /proc/bus/usb (needed by vmware. security!!)
You need to replug your device after removing ehci_hcd module so your device sees the change. Look at /proc/bus/usb/devices to find in which bus you device is in. cat /sys/kernel/debug/usbmon/nt to a file (n is the bus number). Finally pass this file to M920x parse (arguments -i um -m fw)