[goofed]

No information about your hardware...
I had the same problem.

I'd solved this problem adding a new line on [Version] section in AdfuUpdate.inf :

ClassGUID={36FC9E60-C465-11CF-8056-444553540000}

So, my entire AdfuUpdate.inf file:

[Version]
Signature="$CHICAGO$"
Class=USB
ClassGUID={36FC9E60-C465-11CF-8056-444553540000}
provider=%MSFT%
LayoutFile=LAYOUT.INF
DriverVer=11/22/2006,3.3.0.0

[Manufacturer]
%MfgName%=Upgrade

[Upgrade]
%USB\VID_10D6&PID_8888.DeviceDesc%=MDisk.install,USB\VID_10D6&PID_8888
%USB\VID_10D6&PID_ff51.DeviceDesc%=MDisk.install,USB\VID_10D6&PID_ff51
%USB\VID_10D6&PID_ff61.DeviceDesc%=MDisk.install,USB\VID_10D6&PID_ff61
%USB\VID_10D6&PID_ff63.DeviceDesc%=MDisk.install,USB\VID_10D6&PID_ff63
%USB\VID_10D6&PID_ff66.DeviceDesc%=MDisk.install,USB\VID_10D6&PID_ff66
%USB\VID_10D6&PID_ff79.DeviceDesc%=MDisk.install,USB\VID_10D6&PID_ff79

[PreCopySection]
HKR,,NoSetupUI,,1

[DestinationDirs]
umss.files = 10,System32\Drivers

[MDisk.install]
CopyFiles=umss.files
AddReg=umss.addreg

[MDisk.install.NT]
CopyFiles=umss.files
AddReg=umss.addreg

[MDisk.install.NT.Services]
Addservice = AdfuUd, 0x00000002, AdfuUd_AddService

[AdfuUd_AddService]
DisplayName    = %USB\VID_10D6&PID_1160.DeviceDesc%
ServiceType    = 1                  ; SERVICE_KERNEL_DRIVER
StartType      = 3                  ; SERVICE_DEMAND_START
ErrorControl   = 1                  ; SERVICE_ERROR_NORMAL
ServiceBinary  = %10%\System32\Drivers\AdfuUd.sys
LoadOrderGroup = Base

[umss.addreg]
HKR,,DevLoader,,*ntkern
HKR,,NTMPDriver,,AdfuUd.SYS

[umss.files]
AdfuUd.sys

[SourceDisksNames]
1000 = "USB Mass Storage Device",,,

[SourceDisksFiles]
AdfuUd.SYS = 1000

[Strings]
MSFT="MP3Player"
MfgName="MP3Player"
USB\VID_10D6&PID_8888.DeviceDesc="USB ADFU Device"
USB\VID_10D6&PID_ff51.DeviceDesc="USB 2.0 (FS) ADFU Device"
USB\VID_10D6&PID_ff61.DeviceDesc="USB 2.0 (HS) ADFU Device"
USB\VID_10D6&PID_ff63.DeviceDesc="USB 2.0 (HS) ADFU Device"
USB\VID_10D6&PID_ff66.DeviceDesc="USB 2.0 (HS) ADFU Device"
USB\VID_10D6&PID_ff79.DeviceDesc="USB 2.0 (HS) ADFU Device"

But... my problem still. "Flash is no respondig".
And I tried almost all firmware of the world.

Before someone say that, I already tried other versions of Mp3 Utilities and Product Tool.

I received this two MP4: Viola and Pearl Z without firmware!
And I'm not attaining to upgrade this worse firmware!

Please help me...