Hi
Tried the DFU example (without any modifications) from the file lpcopen_2_20_lpcxpresso_nxp_lpclink2_4370.zip.
We uploaded the DFU example to the flash of the LPC-LINK 2. Then reconnected the USB cable and device shows up the USB composite device as shown below

Now we run the command
dfu-util.exe -d 1FC9:89 -c 0 -i 0 -t 2048 -R -D LPCScrypt_140.bin.hdr
dfu-util 0.7
Copyright 2005-2008 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2012 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to dfu-util@lists.gnumonks.org
Filter on vendor = 0x1fc9 product = 0x0089
Opening DFU capable USB device... ID 1fc9:0089
Run-time device DFU version 0100
Claiming USB DFU Runtime Interface...
Determining device status: state = appIDLE, status = 0
Device really in Runtime Mode, send DFU detach request...
Resetting USB...
Opening DFU USB Device...
Found Runtime: [1fc9:0089] devnum=0, cfg=1, intf=0, alt=0, name="UNDEFINED"
Claiming USB DFU Interface...
Setting Alternate Setting #0 ...
Determining device status: error get_status
Next the device switches the DFU mode, goes to an alternate configuration of the USB and shows up as

Again we run the command
dfu-util.exe -d 1FC9:89 -c 0 -i 0 -t 2048 -R -D LPCScrypt_140.bin.hdr
dfu-util 0.7
Copyright 2005-2008 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2012 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to dfu-util@lists.gnumonks.org
Filter on vendor = 0x1fc9 product = 0x0089
Opening DFU capable USB device... ID 1fc9:0089
Run-time device DFU version 0100
Found DFU: [1fc9:0089] devnum=0, cfg=1, intf=0, alt=0, name="DFU"
Claiming USB DFU Interface...
Setting Alternate Setting #0 ...
Determining device status: state = dfuIDLE, status = 0
dfuIDLE, continuing
DFU mode device DFU version 0100
bytes_per_hash=563
Copying data from PC to DFU device
Starting download: [##################################################] finished!
state(2) = dfuIDLE, status(0) = No error condition is present
Done!
Resetting USB to switch back to runtime mode
No valid DFU suffix signature
Warning: File has no DFU suffix
can't detach
And after this, the USB connection is gone, and the device is not responding anymore.