install/55060: 9.0 sysinst does not set a default MBR partition for cobalt

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

>Number:         55060
>Category:       install
>Synopsis:       9.0 sysinst does not set a default MBR partition for cobalt
>Confidential:   no
>Severity:       critical
>Priority:       low
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Mar 09 15:50:00 +0000 2020
>Originator:     Izumi Tsutsui
>Release:        NetBSD 9.0
>Organization:
>Environment:
System: NetBSD 9.0 cobalt RAMDISK kernel
Architecture: mipsel
Machine: cobalt
>Description:
Cobalt firmware requires a Linux Ext2 partition to load a bootstrap binary.

sysinst in 8.1 and prior prepares Linux Ext2 partition in MBR partition
by default if the target disk has empty MBR label.

However sysinst in 9.1 doesn't prepare a default MBR partition
for a fresh disk.

>How-To-Repeat:
Install NetBSD/cobalt 9.0 using a RAMDISK kernel.

---

 NetBSD/cobalt 9.0

 This menu-driven tool is designed to help you install NetBSD to a hard disk,
 or upgrade an existing NetBSD system, with a minimum of work.
 In the following menus type the reference letter (a, b, c, ...) to select an
 item, or type CTRL+N/CTRL+P to select the next/previous item.
 The arrow keys and Page-up/Page-down may also work.
 Activate the current selection from the menu by typing the enter key.
 
 
 Thank you for using NetBSD!
               
                NetBSD-9.0 Install System                     
                                                              
               >a: Install NetBSD to hard disk                
                b: Upgrade NetBSD on a hard disk              
                c: Re-install sets or install additional sets 
                d: Reboot the computer                        
                e: Utility menu                               
                f: Config menu                                
                x: Exit Install System                        
               

---
 :
---

 We are now going to install NetBSD on the disk wd0.
 
 NetBSD requires a single partition in the disk's Master Boot Record (MBR)
 partition table, this is split further by the BSD disklabel.  NetBSD can also
 access file systems in other MBR partitions.
 
 If you select 'Use the entire disk' then the previous contents of the disk
 will be overwritten and a single MBR partition used to cover the entire disk.
 If you want to install more than one operating system then edit the MBR
 partition table and create a partition for NetBSD.

 About 1.3G is enough for a basic installation, but you should allow extra for
 additional software and user files.
 Allow at least 3.0G if you want to build NetBSD itself.

                      
                       What would you like to do?      
                                                       
                      >a: Edit the MBR partition table 
                       b: Use the entire disk          
                      

---

 The Current MBR partition table of wd0 is shown below.
 Flags: (I)nstall here, (a)ctive.
 Select the partition you wish to change:
 
    Total size of wd0 is 14324 MB, available: 14324 MB
 
        Start(MB)      Size(MB) Flag Kind                       Mount
    ------------- ------------- ---- -------------------------- --------
          (no partition defined)
    ------------- ------------- ---- -------------------------- --------
>c: Add a partition
 d: Clone external partition(s)
 e: Change input units (sectors/cylinders/MB/GB)
 f: Cancel
 x: Partition table OK
 
---

8.1 sysinst on the same machine (Qube 2700) shows:
---

 We are now going to install NetBSD on the disk wd0.
 
 NetBSD requires a single partition in the disk's MBR partition table, this is
 split further by the NetBSD disklabel.  NetBSD can also access file systems
 in other MBR partitions.
 
 If you select 'Use the entire disk' then the previous contents of the disk
 will be overwritten and a single MBR partition used to cover the entire disk.
 If you want to install more than one operating system then edit the MBR
 partition table and create a partition for NetBSD.

 A few hundred MB is enough for a basic installation, but you should allow
 extra for additional software and user files.
 Allow at least 5GB if you want to build NetBSD itself.
                      
                       Which would you like to do?     
                                                       
                      >a: Edit the MBR partition table 
                       b: Use the entire disk          
                      

---

 The Current MBR partition table is shown below.    
 Flgs: a => Active partition, I => Install here.
 Select the partition you wish to change:
 
    Total disk size 14324 MB.
 
    Start( MB)  Size( MB) Flg Kind
    ---------- ---------- --- ----------------
>a:          0      14300 a   NetBSD
 b:      14300         24     Linux native
 c:                           unused
 d:                           unused
 e: Change input units (sectors/cylinders/MB)
 x: Partition table OK
 
---

This can also be reproducible on GXemul and NetBSD-9.0-cobalt.iso:
 http://gavare.se/gxemul/gxemul-stable/doc/machine_cobalt.html

>Fix:
No idea.

---
Izumi Tsutsui