KIM Kenner 19 Patches op Basic Hans Otten, translated by Hans Otten, 20211
May 1981 Byte Magzine had an article in System Notes, Faster Basic for Ohio Scientific.
The article described how the first batch of the 6502 had a faulty ROR instruction, so the programmers of Microsoft Basic had to work around this missing instruction with a slower replacement, (Note 2021: this is well explained in the Pagetable MS Basic articles) and how to patch this to really use the ROR instruction and speed up things.
A letter to the editor in a later Byte (September 1981?) showed the patches required for the KB9 KIM-1 version.
Location $37DE to $3801 and $38D2 to $3903 are now unused.
This patch may speed up KB9 quite a bit for number crunching.