new install not booting - solved, but questions remain

[Miles Fidelman]

Hi Folks,

Just installed Debian Wheezy onto a remote server, and encountered some 
problems getting grub to boot properly.  Figured it out through trial 
and error, but an explanation of what's going on would be very much 
appreciated.  Note, most of my familiarity is with grub-legacy, this is 
my first time working through things with grub 2.

Basic setup:
- remote install via IPMI console and later via ssh
- PXEboot into the installer
- partition and configure 4 disk drives into md devices for boot, swap, 
root, LVM
- USB drive shows up as /dev/sda during install - with hard drives as 
/dev/sdb-e
- after install hard drives show up as /dev/sda-d, usb drive as /dev/sde
- pretty standard install process until the end
- had to fiddle a bit to install MBR into hard drives (default would 
have put it on the USB)
- attempt to boot, end up at grub prompt on the remote console
- type "boot" and get "error: no kernel loaded"
- did some googling, based on what I found, tried the following (from 
the grub> prompt)
-- set prefix=(md/0)/boot/grub
-- set root=(md/2)
-- boot
-- still get "error: no kernel loaded"
-- noted that ls (md/0)/ showed System.map, config-, vmlinuz, initrd as 
well as grub
-- tried the command "linux (md/0)/vmlinuz..." - let it autocomplete the 
full file name
----- got "error: file not found"  #THIS IS CONFUSING - SINCE LS AND 
AUTOCOMPLETE FOUND THE FILE"
-- insmod normal
-- insmod
------ now I get a boot screen, and after the timeout, everything booted 
normally
- reboot brought be back to the grub> prompt
- this time, after booting:
-- ran update-grub and grub-install on all four drives, and and on 
/dev/md0 (boot) and /dev/md2 (root) for good measure
-- rebooted - everything came up fine So problem is solved but 2 questions

But I'm left with two questions:
- What exactly is going on? (WHY did the above fix the problem?)
- Why didn't the install set things up properly? (This one is really a 
question for the debian-boot list, and perhaps a bug report - but I'd 
kind of like to understand what's going on with grub, and what should be 
installed, before focusing on the installer.)

Thanks very much,

Miles Fidelman