Releases:
There are several known versions:
Solaris 2.4 - according to this press release. [archived]
Solaris 2.5 beta - Solaris 2.5 PowerPC Edition Hardware Compatability List [local]
Solaris 2.5.1 LAR CD-ROM + floppies [Jan 1996] [download]
Solaris 2.5.1 tape [Apr 1996] available at [betaarchive]
Solaris 2.5.1 LAR CD-ROM + floppies [Nov 1996] [download]

You must use Nov96 Motorola floppy. Jan96 is not working. Both cds Jan96 and Nov96 are installable.






Requirements:

In order to install Solaris 2.5.1 LAR(Limited Availability Release) Nov 1996 you will need the following:
- MVME1600-01 board [minimum of 16MB memory required]
- MVME760 transition board [optional]
- SCSI disk + SCSI CD-ROMs 
- Floppy drive
- Solaris 2.5.1 - Motorola Boot diskette + Solaris 2.5.1/ppc CD-ROM

Install Process:
First, you will have to find a PPC1Bug suitable with 1600. MVME1600 compatible veirsions are PPC1Bug 1.0 through PPC1Bug 2.3
I've tested the installation with PPC1Bug 1.1, 1.9 and 2.3
How to display disk devices:

Version 2.3 for example, supports DEC21140 ethernet chips (MPMC202), however MPMC202 causes Open Firmware not to load so if you have 
this PMC board remove it before booting the OS.
 If you are going to transfer the image over network you will need a MVME760 transition board or MPMC202. You can also transfer the image via Disk, CD, VMEbus etc...
Displaying network adapters (here I have MPMC202), which I later removed:

Make sure the diskette is now write-protected, the Sun installation will write on it and if you fail to install the OS you will have to format/write the diskette again.
PPC1Bug has troubles reading the diskettes written in other environments (dd for example). 
The best way to transfer the content of the boot diskette is over the network via tftp. 
Then you have to format it and write the content from the memory:




Let's boot the diskette:


You are now into Sun's Virtual Open Firmware, which supports booting directly from the CD-ROM.
Note, that you must press any key within 5 seconds to disable the auto-boot procedure.
To list the devices use show-devs at the ok prompt.
As you may noticed, VOP (Virtual Open Firmware) doens't detect the board architecture correctly. 
Sun added official support in VOP 2.0 although I wasn't able to boot from the cd.
It could be a part of the unfinished Solaris 2.6/ppc.


Boot from the CD:



Here is the configuration you need to pick up to have a working X server:
[X] Motorola PowerStack RISCPC (Onboard GD5434....)
[X] IBM Or Motorola Built-in Mouse


At this point the installation is straightforward.

To boot from the disk you will need each time to interrupt Open Firmware's auto-boot process and enter the full boot path manually: