Thanks John, You are correct. It appears to be a stack issue. I've got the initial error resolved but I've still got to do a little more work. Appreciate the insights.
Kurt On Tue, Sep 10, 2019, at 12:18 PM, John R. Hogerhuis wrote: > Seems like you've embedded code in OptROM that you copy to ALT-LCD. > > When you say "the cold start recovery routine of TS-DOS" do you mean the NEC > POKE and EXEC to activate TS-DOS? > > If so it seems your only trigger to do the LINE install is the BASIC ROM's > OptROM install EXEC routine. So whenever the ROM installs, it will fill in > your code into ALT-LCD. > > I can't think of anything that you would have to do different than whatever > TS-DOS does. > > I suspect some stack imbalance, clobbered registers or clobbered RAM > variables. > > -- John.
