Haiku nightly upgrade from USB key

In general, when I had upgraded my Haiku nightly to a more recent version, I have initialized the partition and started from scratch.
But, now that the nightlies are becoming more and more usable, I would prefer to upgrade more frequently without losing my setup.
Then I saw this thread in the forum where a non-destructive upgrade can be done from a usb key.
So, I tried it with Haiku r40448 gcc2hybrid and it went fine. The only difference from what I was doing previously was to avoid initializing the partition before the install.
After the install Haiku r40448 booted fine from Grub2, the old wallpaper showed up as did the mail notifier. However, none of the replicant were there including the clock, workspaces, activity monitor and the volume slider. All of the apps I had installed on the older version were still there and working. In WebPositive, even the Google background image was the same as before.
However, LaunchBox did not launch at boot because /boot/home/config/boot/UserBootscript had lost the startup applications I had previously added.
Nevertheless, to get them back was just a matter of copying the file over from the Home folder of the previous version which I had stored on another partition.
Now we come to the biggest, and only serious, issue that I had -- sound.
Although oss was still installed, the driver /boot/system/add-ons/kernel/drivers/bin/hda did not remain in the "disabled" form in which I had left it in the old nightly.
This is understandable as the system directory is the only one that gets completely substituted by the new one. All of the others are "merged" although I'm not quite sure what that means in this context but it sounds quite benign.
To get it working, I just followed what I had already posted here a while back, particularly the "disabling" of the hda driver.
Then it was necessary to got to Deskbar>>Preferences>>Media and unmute all of the sound settings.
Finally, I clicked on the Volume icon in the Deskbar (enable by checking box in the Media Preferences dialog) and choose Option>>Control physical output.
However, I admit I'm not totally sure if this last one is essential.
Now I could play mp3's in VLC.
Mysteriously, however, osstest which has served me well in Haiku on this machine (Dell E520) still would not play and complained about Intel HD Audio Control being in use.
I posted to the haiku forums about this but have not yet received and answer.