Summary: How to force booting from a floppy on RT after changing NVRAM?

[karl at tobago.cgd.ucar.edu]

The answer was to unplug the battery backup inside the 6150 system unit
	for an hour. After doing this, it booted up fine from the DIAGS
	Diskettes. The battery backup unit is inside the front cover.
	There is little blue and white cable. Just pulling it straight
	down unplugs it. It has three pins that only go one way, when
	plugging it back in.

Here was the original posting-

>I stupidly changed the NVRAM in my RT to boot from who-knows-what. How do
>        I get the thing to boot from the diags diskette in the floppy
>        drive? Upon power up, or <CTL><ALT><PAUSE>, some numbers flash on
>        the LED, then it beeps and hangs with the LED readout saying 29.
>        Any clues? Please email and I will summarize.

Another solution was to try the keyboard sequence <CTL-ALT-A>. This was
	supposed to change the values in NVRAM to boot from the floppy. I
	could not get this to work. I think I have learned that error code
	29 means it is trying to IPL from something. It appears there are
	a large number of keyboard sequences that may be used on the RT.

I am including the following message, which was excerpted from Francis
Demierre, in the hopes that it might be usefull.
Organization: Hasler AG, CH-3000 Berne 14, Switzerland
Unix Mail: francis at hslrswi.UUCP


1. Set the boot device with one of:

    Ctrl + Alt + a : Updates NVRAM for diskette device #1
    Ctrl + Alt + b : Updates NVRAM for diskette device #2
    Ctrl + Alt + c : Updates NVRAM for fixed-disk device #1
    Ctrl + Alt + d : Updates NVRAM for fixed-disk device #2
    Ctrl + Alt + e : Updates NVRAM for fixed-disk device #3

2. Reboot your machine with:

    Ctrl + Alt + Pause: Perform a soft re-IPL
                        Reboots from the device specified with the
                        Ctrl + Alt + (a,b,c,d,e) combination.

Other special sequences are:

 Ctrl+Alt+Home:     Performs a re-IPL of the virtual machine
 Ctrl+Alt+Pad6:     Performs a power on reset re-IPL (cold start)

 Ctrl+Alt+Pad7:     Performs a dump of all real memory
 Ctrl+Alt+Pad8:     Performs a dump of selected area of memory
      Note for the two seq. above:
         1. if the "c6" code already displays, insert
            a dump diskette and press the sequence.
         2. if you want to initiate a dump at any time, press this sequence
            (c6 appears), insert a diskette and issue the sequence again.

 Ctrl+Alt+Pad4:     Invokes the VRM debugger
 Ctrl+Alt+End:      Performs a dump of the first virtual machine
 Ctrl+Alt+Del:      Performs an IPL of the optional coprocessor
 Ctrl+Alt+Action:   Exits from the coprocessor mode (after a 'pcstart')

 Alt+Action:        Change the active display screen to the next virtual
                    terminal (if any). (after an 'open' command or 'pcstart',
                    etc...)
 Shift+Action:      Change to the previous virtual terminal.
 Ctrl+Action:       Change to the command virtual terminal (if defined)

Thanks to:

Dan Ehrlich
Chuck Karish		karish at mindcraft.com
Francis Demierre <francis at hslrswi.UUCP>
aesnet:moody at moody.austin.ibm.com
Paul Chamberlain

		thanks again,
			Karl Sierka

--
Karl Sierka sierka at ncar.ucar.edu 
1850 Table Mesa Drive, Boulder, CO 80301 (303)-497-1338	
Disclaimer: The opinions expressed are not those of my employer.
"Can GOD write a program so complicated that even He/She can't debug it?"