Ubuntu :: Migrating Quad-boot Setup - Console Screen Doesn't Even Clear

I know that these forums aren't M$ support forums, but any mention of Linux and open source there just ends up in "don't use Linux"-type replies, so i figured i should ask it here. I have a quad-boot setup (Win7x64-Win7x64-K9.10x64-K9.10x64). I am in the process of migrating this setup to another (bigger) HDD. The Win7 system partitions were cloned using 3rd paty imaging software, Linux system partitions were cloned directly (cat /dev/sda5 > /dev/sdb5), data partitions were freshly created and populated with files copied from old partitions.

As the hard drive is bigger than previous one, i decided to add a little more space to Win7 system partitions. So when creating new partitions, i left 5GB unallocated space between them in order to grow the partitions later. I cloned the new partitions, ran the chkdsk with all options on to make sure the resulting partition survived the migration, then checked if it is readable under Linux (it was), used KPartitioner to grow the partition to the new size, again booted into Win7 Recovery, ran chkdsk with all options on, removed bootloader and made a new one using bcdboot.

Now, my Linuxes boot OK (there was some wankery involved but nothing too serious), but neither of my two Win7 can. I checked the bootloader, fiddled with different settings (e.g. removed setting the root by UUID), even tried to manually boot it from commandline - to no avail. After "chainloader +1" and "boot" it just does nothing. No error messages, nothing at all - the console screen doesn't even clear.