Changing the Apple //c Startup Text

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RadioC1ash's picture
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Changing the Apple //c Startup Text

I've been just reading Fuji's writeup from a few years back on adjusting the startup text on an Apple IIe by changing some of the ROM's code. I wondered if a similar operation could be performed on a IIc, and if anyone might have some experience with that or any other modifications to a //c ROM. 

Obviously the code on the IIc is quite different from that of other Apple IIs. What I've found looking at the ROM 0 code that I've dumped is that there isn't any string that matches what the default title text says. Indeed, not even "app" or "//" can be found. So, I assume it's been obscured in some way on the IIc that it wasn't on the earlier models.  

Background is that my son is super into filmmaking and our collection gets some use in his film projects. Similar to how we saw a TRS-80 in Andor, we like to use real vintage computers as in-universe props. Such a mod would allow us to create a neat effect for filming.  

Anyhow, since this appears to go beyond simply modifying the ASCII text on the ROM in this case, I'm afraid I'm out of my depth. Any help would be super appreciated!

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The Title string in the Apple

The Title string in the Apple //c ROM is found at offset $3D03. It is in normal Apple style with the high bit set which is why you might not have found it. You can change this string all you want as the old "Apple ][" string is also present in the original location; this is what ProDOS checks to make sure it isn't running on a clone.

 

The ROMXc product makes it very easy to create and use custom ROM images any time you want!

 

 

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It always confuses me when I

It always confuses me when I use a modern tool to dump or view Apple ROMs.  I usually end up reverting to old fashioned tools on a real Apple II - I dump ROMs using an old slot-card EPROM writer and view (and modify) the code using a vintage tool like Blockwarden (which is included in the latest ProDOS 2.4 distribution from John Brooks) to view (and possibly modify) the ASCII characters in Firmware.

I recall back in the 80s changing my II+ Clone's F8 ROM that had the bootup string "COMPUTER" to "APPLE ][" so that I could run ProDOS without having to patch each diskette.

 

 

 

 

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I was reasonably confident

I was reasonably confident that I was missing something kinda silly! Thank you. I'll get a ROMXc on order. I've ordered two for Apple IIs already. Seem to work great, and this sounds like a much handier option for our purposes anyway. 

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