VG8020 / 40 and dirty memory after hardware restart.

Por DaikuMaryuGaiking

Expert (126)

imagem de DaikuMaryuGaiking

15-04-2020, 11:37

Hi!
Using the VG 8020/40 I noticed that some games loaded from a cassette remain in memory, or in part, after the machine is turned off. From some friends of MSX Italia I learned that this defect does it also to other owners of this model.
I have to wait many minutes and turn on the machine several times to have a clean memory and 28815 bytes free.
Is there any way to clear memory properly on startup?

Thank you.

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Por Manuel

Ascended (19270)

imagem de Manuel

15-04-2020, 12:22

1. Don't run ROM cracks Smile
2. If you still want to run ROM cracks, remove the AB bytes.

Por pgimeno

Champion (328)

imagem de pgimeno

15-04-2020, 12:59

Manuel, option 2 doesn't help if you can't access BASIC. EDIT: Oh, you mean from the program in tape. Never mind.

For me it's around 1 minute, by the way.

Por DaikuMaryuGaiking

Expert (126)

imagem de DaikuMaryuGaiking

15-04-2020, 16:25

Manuel wrote:

2. If you still want to run ROM cracks, remove the AB bytes.

How do it? ....an example? Somehow, the files are CAS.

Por Manuel

Ascended (19270)

imagem de Manuel

15-04-2020, 18:09

Binary edit the cas files? Find AB bear the beginning of a block and change into something else like 00 00. Then try again.

Por tfh

Prophet (3304)

imagem de tfh

15-04-2020, 18:29

Manuel wrote:

Binary edit the cas files? Find AB bear the beginning of a block and change into something else like 00 00. Then try again.

I doubt this is enough help...

Download https://www.mitec.cz/hex.html
Drag & Drop the .CAS files on this editor and do a text search for the letters AB (41 & 42 in hex code). Replace these with 00 00 and save the .CAS file and try again.

Por Manuel

Ascended (19270)

imagem de Manuel

15-04-2020, 19:18

Be careful not to replace all... replace and test. You probably only need to replace one.

Por DaikuMaryuGaiking

Expert (126)

imagem de DaikuMaryuGaiking

16-04-2020, 13:33

OK!! IT WORKS! I've modify "AB" then 41&42 i hex code with 00 & 00 on bin part.
It works.

Thanks.

Por Manuel

Ascended (19270)

imagem de Manuel

17-04-2020, 00:45

Great! Big smile