http://www.rtoadm.com/Update_501100064_501108064.bin
That's the site I host my blog on, has unlimited bandwidth so feel free to pass it around.
Note: I have not tested this since I captured it off my K2 after it updated, so it's at your own risk.
The tool I used said the file appeared to be intact, so it should be good, but as stated this is at your own risk and I'm not responsible if it bricks your device.
2nd Note: It's also most likely just a 2.5.4 to 2.5.6 Update. Any confirmations on that are welcome.