Try this
[x2 Player Speed (HOLD B) 1.1]
040A0000 021dff1c 1E2E1000
80000002
040A0000 021dff1c 1E201000
20000000
I do not know (yet) where battle speed is located.
is that a typo for 2x? 1E201000
does it make sense for the value of 2x speed (20) to be lower than 1.0 speed (2E)?
i didn't try.