Just a couple of shots in the dark. Although the HD44780
has become a sort of standard, some driver ICs do differ
slightly

In a couple of cases using LCDs with the MSM6222 I've
needed to slow down the rise time of E with a few hundred
pF to ground - then it miraculously comes to life. Apparently
the orientation of the E wire and PCB traces can cause
EM induction problems

The other thing to look at would be timing. The HD44780
has a nominal Busy timeout for most instructions of 40us
and a 6us period after Busy is released when RAM can't
be read/written. Other controllers have different figures
for this. For example they may still be working on internal
register updating during the Busy period and so not have
a 6us post-Busy timeout

Also take a look at the time for particular operations. eg the
HD44780 is around 600Hz (~1.7ms) for a repeated "display
clear" instruction, for the MSM6222 it's only 80Hz (~13ms).
Not that you'd be repeatedly clearing the display but the timing
differences could also apply to other parameters

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