GPT missing after controller swap (wd to ld)

[Louis Guillaume <louis%zabrico.com@localhost>]

Hi,

On NetBSD 7.0_STABLE, i386, (from earlier this year) I had configured a 
couple of disks with GPTs and then switched controllers (wd1 now shows 
up as ld1) and now the GPT appears to have gone missing. However my 
wedges are still there...

# gpt show ld1
gpt: error: map entry doesn't fit media
gpt: unable to open device 'rld1d': No such file or directory

# dkctl ld1 listwedges
/dev/rld1d: 2 wedges:
dk0: boot0, 524288 blocks at 128, type: ffs
dk1: disk0, 3906504704 blocks at 524416, type: raidframe

The first wedge is intended to just hold a kernel and emergency root 
file system for booting. The root file system is on a raid array built 
with dk1 (and others). I'm currently booted off a separate disk because 
the bootmenu did not include the boot.cfg "installboot"-ed to ld1.

Did something in the BIOS overwrite the GPT? How to recover?

Louis