SD512 (by 8bit4ever) on MSX1 (HB-101)

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By odaman68000

Rookie (21)

odaman68000's picture

17-02-2018, 09:46

Hi guys!
I tried SD512 on MSX1 HB-101, but it didn't work with Nextor.
In my knowlege, SD512 should provide 64KB(and 512KB with mapper), so MSX can boot Nextor and load DOS from SD card.
But it doesn't work, HB-101 boots only disk basic. (and can not access to SD.)
My HB-101 is japanese version, and it have only 16KB of RAM (located at C000h on slot#0).

Can anyone let me know why?

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By Pentarou

Master (223)

Pentarou's picture

17-02-2018, 13:39

You can't boot to Nextor unless it's already installed into your SD card.
Find a way to bypass the HB-101 firmware, format the SD card and install Nextor in it, then it will boot.

And obviously the switches have to be in the correct position, otherwise the RAM isn't seen.

By odaman68000

Rookie (21)

odaman68000's picture

17-02-2018, 16:21

Thanks for your comment, Pentarou.
Of course, there's some neccesory files on SD for booting nextor. And nextor can be booted without any probrem on MSX2 FS-A1(64KB RAM).
Only HB-101 can not boot nextor, and I want to know the reason why it can not be booted.

By Pentarou

Master (223)

Pentarou's picture

17-02-2018, 16:51

How much RAM does the disk basic prompt show? "23432 Bytes free" or less?

By odaman68000

Rookie (21)

odaman68000's picture

18-02-2018, 01:18

It shows "24925 bytes free" after booting Disk-Basic.
I'm using 2GB SD Card for Nextor boot.
Maybe HB-101 will boot MSX-DOS1, but 2GB SD card is not recognized in DOS1.
(I don't have FAT12 capable size of SD card...)

By Pentarou

Master (223)

Pentarou's picture

18-02-2018, 17:11

I don't' think that the computer needs an MSX-DOS1 partition, I tested the SD512 on a 16KB MSX1 and it booted Nextor without any problem.
If it shows more than 16Kb free then it means that the 512Kb RAM is seen and used, maybe there's a problem with your partition?
How did you format the SD Card? If you did it on a Windows/MAC/Linux machine then maybe it's not recognized, try to format it again on an MSX with the CALL FDISK command.

By odaman68000

Rookie (21)

odaman68000's picture

19-02-2018, 02:42

I finally succeeded to boot Nextor on 16KB MSX1 HB-101.
I examined HB-101's slot configuration deeply, and found the custom firmware is located at slot #3 $4000-$7FFF.
It's a small utility for manage the telephone number and so on, but now a days it's not useful. (who use this?)

I open the HB-101 and found the mask ROM chip, and cut off the CS line. (and this firmware ROM is cut off.)

And next, HB-101 boots Nextor without any problem!
I think that slot #3 ROM had been prevented the booting of Nextor.

Pentarou, thank you for your comment !!!

By gdx

Prophet (3037)

gdx's picture

19-02-2018, 09:11

The best is to desolder the ROM or replace it with an eeprom. Actually, it's better to remove most of firmwares from MSX1 or MSX2.

By wcwmans

Supporter (7)

wcwmans's picture

27-06-2018, 22:15

hi,
i have the same problem with the msx sd mapper/megaram and the hb 101.
nextor run see my 2 sd card and jump to the phone application menu in japanese.
i understand that you have cut the cs line 3 at the slot #3 $4000-$7FFF, it means that you have cut the eprom number 3 metalic stuf ?
I can't identify the slot 3.
if you have any picture or more information to help me please
thank you

By Manuel

Ascended (15750)

Manuel's picture

27-06-2018, 22:35

Isn't there a hot key to skip the boot of the firmware? That's really annoying!

By mxmy

Resident (39)

mxmy's picture

28-06-2018, 06:10

Have you tried booting holding down either the 'ESC' or 'F4' key? I find one of these often helps my MSX bypass the firmware on boot, though I do have a different model...

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