port-amd64/59207: unexpected behavior of dev command in bootstrap code

[paul%whooppee.com@localhost]

>Number:         59207
>Category:       port-amd64
>Synopsis:       unexpected behavior of dev command in bootstrap code
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Mar 23 11:00:00 +0000 2025
>Originator:     Paul Goyette
>Release:        NetBSD 10.99.12
>Organization:
+---------------------+--------------------------+----------------------+
| Paul Goyette (.sig) | PGP Key fingerprint:     | E-mail addresses:    |
| (Retired)           | 1B11 1849 721C 56C8 F63A | paul%whooppee.com@localhost    |
| Software Developer  | 6E2E 05FD 15CE 9F2D 5102 | pgoyette%netbsd.org@localhost  |
| & Network Engineer  |                          | pgoyette99%gmail.com@localhost |
+---------------------+--------------------------+----------------------+
>Environment:
	
	
System: NetBSD speedy.whooppee.com 10.99.12 NetBSD 10.99.12 (GENERIC) #0: Wed Mar 19 03:32:11 UTC 2025 paul%speedy.whooppee.com@localhost:/build/netbsd-local/obj/amd64/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:
In the final stage bootstrap code (where the menu of boot selections
is presented, the dev command does not appear to work when included
in the boot.cfg file; the default device does not get updated.  When
entered interactively (from the ``boot prompt'') it works as one would
expect.

The problem occurs in both "standard" and "efi" bootstrap code (files
/usr/mdec/boot and /usr/mdec/bootx64.efi) so probably lives in common
shared code.
	
>How-To-Repeat:
1. Install a base VM system - the system created by sysutils/anita works
   fine for this step.

2. Boot the resulting VM, login as root, and edit the /boot.cfg file to
	a) add a failsafe menu entry #4, just in case it works!
	b) add an invocation of the ``dev'' command to select a different
	   default device

   The following boot.cfg is useful here:

	# more /boot.cfg
	menu=Boot normally:rndseed /var/db/entropy-file;boot
	menu=Boot single user:rndseed /var/db/entropy-file;boot -s
	menu=Drop to boot prompt:prompt
	menu=Boot normally:rndseed /var/db/entropy-file;boot hd0a:/netbsd
	default=1
	timeout=5
	clear=1
	dev=fd0a:

3. Boot the VM, drop to the boot prompt, and observe that the default
   device has not been set:

	<Banner removed for brevity>

	     1. Boot normally
	     2. Boot single user
	     3. Drop to boot prompt
	     4. Boot normally

	Choose an option; RETURN for default; SPACE to stop countdown.
	Option 1 will be chosen in 0 seconds.     

	Option: [1]:3
	type "?" or "help" for help.
	> dev
	disk hd0 size 25 GB
	  hd0a(NetBSD FFS) hd0b(NetBSD Swap)
	disk fd0
	  fd0a
	disk fd1
	  fd1a
	default hd0a
	> 

4. Enter the dev command manually and note the default device updates:

	> dev fd0a:
	> dev
	disk hd0 size 25 GB
	  hd0a(NetBSD FFS) hd0b(NetBSD Swap)
	disk fd0
	  fd0a
	disk fd1
	  fd1a
	default fd0a
	>

>Fix:
Please

>Unformatted: