[Coco] enable no-halt disto driver

[Mike Pepe]

> If you want additional help, you are going to have to report an exact 
> description of what you are doing. Generalizations mean nothing when it 
> comes to troubleshooting. Posting, "It doesn't work!" or "I can't make 
> it work." will get you nowhere.
> 
> So, post the contents of your mb and bootlist files. Which version of 
> NitrOS-9 are you working with? Is this on an emulator or real Coco 
> system? Specify in detail the hardware or emulator being used. What 
> disks are in which drives and what are the drive specs?
> 
> You have implied you are using a Disto SCII but have not really said you 
> are. So, do you have this controller or are you just trying to use the 
> drivers with a normal controller? If you have the controller, what are 
> the jumper settings, ie. is $FF58 or $FF74 I/O in use?
> 

Rob, that wasn't enough detail for you? heh

Certainly. This is a real 512k CoCo 3 with a 6309. Playing with nos9 
3.02.06 and a real Disto SC2.

I extracted the bootlist from the floppy image on a linux box with 
toolshed. I commented out the tandy 1773 line and removed the comment 
from the $FF74 version of the SCII driver.

I put it back into the image,and wrote the resulting image with omniflop 
on my doze box (because that f{blank}ing pile of crap fdutils is almost 
as useless as the mailing list that "supports" it, but I digress)

Then booted the resultant disk, did a dmode on /d1 cyl=50 and ran the mb 
script to build a new disk in /d1. The disk is formatted correctly.

Step 2 (creating custom boot track) completes

Step 3 (create the bootfile and boot track) always blows up. this run, 
for instance, I got:

./MODULES/SCF/m1.dd
ERROR 216

and then it drops to step 4, where it copies shell and grfdrv over.

The resulting disk is not bootable.

This happens even if I do it from the stock image with the stock 
bootlist file.

So, either I'm doing something wrong, I have a bad floppy image, or I 
found a bug.

-Mike