re: How to recover a root partition with damaged boot blocks

[matthew green <mrg%eterna.com.au@localhost>]

things to do:

- reinstall bootxx_ffsvN -- make sure you're installing the right
  ffsvN.  you can use "dumpfs <device> | head -2", and it should
  say FFSv1 or FFSv2 here.  that's "installboot" that you may have
  already done, but perhaps used the wrong one?

- re-copy /boot.  cp /usr/mdec/boot /

- re-copy your /netbsd (where ever it came from)

- uefi wants a MSDOS partition with /efi/boot/bootx64.efi, so if
  you haven't provided that it won't work.  if you have enough
  space at the start or end of the disk you probably can do this,
  as it only needs to be pretty tiny.  i did this on a system where
  root started at sector 2048, and i was able to create about 700KB
  file system, and bootx64.efi is only about 230KB.  it normally is
  ok with mbr _or_ gpt partitions here.

- check that the fdisk (gpt?) and disklabel are OK.  ie, run both
  "fdisk wd0" and "disklabel wd0" and compare to your working
  system, see if anything stands out.

HTH,


.mrg.

ps see "man 7 entropy" for how to fix the problem you observed.