OS3.9 and OS4.0 in the same Amiga...

[flaviosr]

countzero wrote:
os 4 needs to run setpatch and start again. so be sure to catch the second boot and disable dh0 again.

an easier method is to give a higher priority to os 4. this way it will directly boot to ps4 without any problems. for os 3.9, you need to enter boot menu and select dh0 for boot device. but remember, if you have romupdate patches in your setpatch, it will restart, so you need to catch it and select dh0 again.

I have a 3.9 rom in my system, so I skip romupdates, which boots to 3.9 without any restart.

I have modified so that now I have DH0, priority 0 (OS3.9) and DH1, priority 1 (OS4.0).
OS4.0 is ok but, when I disable DH1, OS3.9 does not start!
The Amiga asks me for a floppy in DF0!!! Really strange.
I have OS3.9 plain right now (I am still in a WIP. Base installation + IDEFix + Picasso96 + MUI...

[Matt_H]

Are the bootable flags both set?

Remember that when rebooting from OS4 to OS3, you need to use the new Ctrl+Alt+Alt combination to force a hard reset and get the OS4 modules out of RAM.

Also check your Kicklayout file to find out how to add a BootDevice module to force OS4 to boot from a specific device, regardless of priority.

[zipper]

You need to get rid of resident patches, meaning at least 10 seconds power off.

[spirantho]

I have my 4.0 partition first on the hard disk (1GB) and my 3.9 partition second. They have priorities 3 and 2 respectively. When I want 3.9, I load Media Toolbox in OS4 and change the priority of HD0: (the OS4 drive) to 1, and then reboot (remembering to hold down Ctrl-Amiga-Amiga for a few seconds so it flushes the OS4 out properly).
It'll then boot into OS 3.9.

When I've done with 3.9, I go into HDToolbox and change the priority of HD0: back to 3, and reboot. Hey Presto, back to OS 4.


(Remember when you're choosing to boot OS3.9 from the early-startup menu (which can be done), the first thing it does is call SetPatch and reboot. Hence you still need to go into the early start-up menu a second time. If you change priorities as above though you don't need to worry about this.

[Framiga]

"I have my 4.0 partition first on the hard disk (1GB) and my 3.9 partition second. They have priorities 3 and 2 respectively. When I want 3.9, I load Media Toolbox in OS4 and change the priority of HD0: (the OS4 drive) to 1, and then reboot (remembering to hold down Ctrl-Amiga-Amiga for a few seconds so it flushes the OS4 out properly)."

eh? no need to change anything.

when you need to boot to 3.9, cold reset from AOS4 with CTRL+ALT+ALT .... enter in the earlySS without disabling anything, chose the 3.9 partition....  boot then enter another time in the earlySS and chose again th 3.9 partition.

AmigaOS4 pri 4

MOS pri 3

AmigaOS3.9 pri 1

Note- if you have IdeFix on 3.9, the thing is different ... another round to earlySS is required.

[spirantho]

There's no need to change anything, no....

.. but sitting there with mouse buttons held down for ages, clicking a button, then waiting again, and clicking the same menu option is a lot harder than quickly changing the boot priority and rebooting.

It's a matter of preference, really.... but it's possible my A4000 takes longer to boot to the early startup screen than your machine which may make a difference.

[Framiga]

well, probably having everything on the UWSCSI chain (IDE disabled) it helps! :-)