FLIP only works on 9600

[aleksa]

I've made two programming cables,
both with the same result:
the AT89C51ED2 can only be programmed
with the lowest speed, 9600.

First cable had MAX232 directly on RS232,
then 1m flat cable to C51.

Second cable has 1m flat cable from RS232 to MAX,
then 20cm to C51.

GND is between every wire.

I can connect on max 57600,
and successfuly read the flash,
but cannot program it on 57600.
Programming only works on 9600.

I have 20MHz crystal with two 33pF caps.
Using the scope, the freq is closer to 21MHz, though.
I've tried 3 crystals, all are the same.

Any ideas what I should do in order to use 57600?

I've placed a schematic I'm using:
http://users.beotel.net/~astancic/AT89C51ED2.gif

[aleksa]

To reply to myself: CPU freq is the only issue.

After boosting CPU freq to 48MHz, I can now use 115200.