[LAU] Two exact same drumpads, different USB ID's

Dear all, I got two cheap drumpads here that are _exactly_ the same, also on the inside (PCB's have the same revision ID): http://dx.com/p/portable-roll-up-usb-drum-kit-118841 But they get recognized differently, one as an USB MIDI device and the other as an USB HID device. And when it gets recognized as a HID device it's pretty useless because I can't hook it up easily to software that accepts MIDI input. This is the "working" drumpad (the one that gets recognized as an USB MIDI device): /var/log/syslog: Mar 3 13:09:40 piertje kernel: [ 864.820341] usb 5-2: new full-speed USB device number 2 using uhci_hcd Mar 3 13:09:40 piertje mtp-probe: checking bus 5, device 2: "/sys/devices/pci0000:00/0000:00:1d.0/usb5/5-2" Mar 3 13:09:40 piertje mtp-probe: bus: 5, device: 2 was not an MTP device Mar 3 13:09:40 piertje kernel: [ 865.123664] usbcore: registered new interface driver snd-usb-audio Mar 3 13:09:40 piertje pulseaudio[2044]: [pulseaudio] module-alsa-card.c: Failed to find a working profile. Mar 3 13:09:40 piertje pulseaudio[2044]: [pulseaudio] module.c: Failed to load module "module-alsa-card" (argument: "device_id="1" name="usb-UTECK_MIDI_DRUM-00-DRUM" card_name="alsa_card.usb-UTECK_MIDI_DRUM-00-DRUM" namereg_fail=false tsched=yes ignore_dB=no deferred_volume=yes card_properties="module-udev-detect.discovered=1""): initialization failed. lsusb: Bus 005 Device 002: ID 0218:0001 Hangzhou Worlde This is the non working drumpad: /var/log/syslog: Mar 2 20:49:45 piertje kernel: [ 3040.388297] usb 5-1: new full-speed USB device number 7 using uhci_hcd Mar 2 20:49:45 piertje mtp-probe: checking bus 5, device 7: "/sys/devices/pci0000:00/0000:00:1d.0/usb5/5-1" Mar 2 20:49:45 piertje mtp-probe: bus: 5, device: 7 was not an MTP device Mar 2 20:49:45 piertje kernel: [ 3040.602562] generic-usb 0003:1941:8021.0001: hiddev0,hidraw0: USB HID v1.10 Device [HID 1941:8021] on usb-0000:00:1d.0-1/input0 lsusb: Bus 005 Device 005: ID 1941:8021 Dream Link WH1080 Weather Station / USB Missile Launcher So my questions are, why does this happen? The PCB is extremely simple and only has one small IC. Is the USB ID determined by this IC? And the big question, can I trick this non working pad to get recognized as a valid USB MIDI device? I already looked into this (unbinding, binding, new_id) but can't get it to work. And I'm 100% sure these pads are exactly the same. I could use this: https://code.google.com/p/drumroll/ But I get the idea this is not necessary. drumroll also already consumes 4% CPU on my notebook and I want to use this drumpad with my Raspberry Pi, besides, it's extra overhead and only runs SUID. So anybody any idea how I could trick my system in properly recognizing this non working drumpad? I don't mind hacking kernel modules if that would be necessary. Thanks in advance, Jeremy