/boot/loader question

[walt]

Short preamble to my question:  I just bought a new (incredibly cheap!)
hard drive.  I'm using a third-party partitioning tool (Acronis) to
copy my existing DFly partition to the new hard drive.

The Acronis copy-tool offers to copy the existing DFly partiton as
either a primary or logical partition.  Just out of curiosity I
copied it as a logical partition -- which of course led to a
problem:

I used grub to boot /boot/loader from the newly copied partition,
which worked just fine.  The problem came when /boot/loader could
not 'find' /kernel.

When I used Acronis to convert the new logical partition back
to a primary partition then everything worked as expected.

My question:  is there any inherent limitation in /boot/loader
which would prevent loading the kernel from a logical partition?