I think from memory, I downloaded the noobs 1.3.12 image from the RP site
and looked for boot files that had a date of 31st January or later
bootcode.bin and then everything out of boot.tar.xz
Overwrote the corresponding files on the Squeezeplug image, and then it booted OK.
First thing I then did was run the Pi updates in the Squeezeplug setup routine, in order to grab anything else fundamental that might have been missing
I can't offer any warranty on this working for you, but it worked for me.
I'm sure that Thomas will be releasing a new dot release of Squeezeplug 7.5 soon that will boot a Pi2 straight away, but maybe he is waiting to get a Pi2?