06.039 How can I boot ProDOS on my Franklin computer?
Description
This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
06.039 How can I boot ProDOS on my Franklin computer?
In an old Apple Clinic note, Stephen Craft listed specific locations to
change after your Franklin freezes. You could then restart via a 2000G from the
monitor. Here is an updated listing showing the locations to change for several
versions of ProDOS:
v1.1.1 $269E: EA EA
v1.4 $282B: EA EA
V1.6 $282B: EA EA
v1.7 $282B: EA EA
v1.8 $2836: EA EA
v1.9 $2865: EA EA
v2.0.3 $2836: EA EA
It turns out that the bytes Stephen was diddling are D0 03 in the sequence
69 0B D0 03 A5 0C 60. The sequence is near the end of a routine that checks
for the "APPLE ][" string found in all genuine Apple II ROMs but not in most
Apple II clone ROMs.
To fix the booting problem, do this:
Start Copy II+ and select "Sector Editor"
Swap-in the ProDOS diskette
READ Track 0, Sector 0
Search for (Hex bytes): 69 0B D0 03 A5 0C 60
When you find the above, change the D0 03 to EA EA
and write the changed sector back to diskette.
The patch eliminates the checksum test/branch and allows ProDOS to boot on
Apple II clones which would normally fail the check. This patch has no effect
on ProDOS functioning on regular Apple II's.
The above patch is absolutely necessary to get a bootable ProDOS working
for many Apple II clones. Jim Sather (inCider, March 1986) recommends a second
patch which is optional. It prevents ProDOS from erroneously reporting that a /
/e-style 64K 80-column card is present when running on a Franklin.
Note: This patch should not be applied except by Franklin 1000 and, possibly,
some other clone users. On a //e, //c or IIgs it causes ProDOS to not see an
80-column card or some extra memory.
The patch is not needed for Franlin 2000 series machines (the ones that emulate
a IIe and IIc) or any of the Laser 128 series. You would not want to apply the
patch to these units because they have emulated 80 column cards and 128k
(expandable to 1MB on Lasers).
To do the patch, procede as described for the main patch and also do this
...
READ Track 0, Sector 0
Search for (Hex bytes): AE B3 FB E0 38
When you find the above, change it to A2 EA EA E0 38
and write the changed sector back to diskette.
_________________________
By: Rubywand
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