1mb+ Chip RAM on A500 rev 6A / 8A.HELP!!!!

[AmiJIm]

Hi there,
i am having some trouble with the +0,5mb trick on the Amiga 500 Rev 8A.
On the pcb it has printed A500+ rev 8A fat agnus 8375
but hat has 0,5mb chip ram.
i soldered 4 chips M5M44256BP -8
ORIGINAL 4 CHIPS MB81C4256-10P

I DID THE jumper trick
but i still have 0,5 mb ram.,
Are the chips i used compatible?
Does anyone has 8 chips for sale?
or better yet 12 chips?
thnak you.

[AmiJIm]

[AmiJIm]

Hi again,
i have both rev 6a and 8a.
Both have 512kb from factory
and both supports the above way of upgrading.
All i am asking is if the above codes on the rams are suitable for this trick,
i mean , are they 44256type?
Can you identify them??
I got them form ISA VGA cards.
thank you.