Re: Amtech RF512C DOS: differences to 1571 ROM (was: Amtech RF512C manipulates reading the ROM image with M-R)

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Wed, 6 Oct 2021 20:33:39 +0200 Message-ID: <ad06a406-2b9b-6b09-1365-fe1aa2093470_at_laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 10/6/21 8:07 PM, smf wrote:
> The main reason for fixing the checksum would be to make it harder for
> anyone who then wants to rip off your hack and change it ;-)

They could then easily add the RTS to disable the test.

> On 06/10/2021 17:47, Mario Kienspergher wrote:
>>
>> Well, the 157x checksum algorithm is somewhat ... special. :-)
>> I guess they were too lazy (not saying too stupid) to fix it.
> 

Oh, Commodore did the same. Take a look at the 318045-02 ROM for the 
1581. Whoever fixed that little SEI-bug in there decided they didn't 
have time to fix the checksum and disabled the test.

  Gerrit