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Emu Firmware 0.6: Formatting the HD20

Firmware 0.6A-F14 now supports formatting the emulated HD20 disk from the Finder. This is handy for creating new hard disk images without the aid of programs like Mini vMac or Basilisk II. Just grab any random file of 100 MB or so (or create a new one using DD under Linux), name it HD20.dsk, and put it on the SD card. If you boot the Mac from another disk, it will see the HD20 disk image, but won’t recognize it as a valid Macintosh disk. The Finder will ask if you want to initialize the disk – answer yes. Be aware that formatting large disk images can take several minutes, during which there’s no on-screen feedback that anything is happening.

While working on this firmware, I encountered more mysterious errors and spontaneous reboots of the sort I described with firmware 0.5A-F14 on my original purple prototype board. But this time it was happening on another board. I rearranged some code, and the problems mysteriously went away, and even the balky purple prototype board started working fine again. I can’t explain what was causing those errors originally though, so maybe I fixed them, or maybe I just papered over them and there’s still a problem lurking somewhere. Please let me know if you experience any of these issues with this firmware 0.6A-F14:

  • Emu consistently says there’s no SD card, when there is. Even after reboot, reset, reinsert card.
  • Emu in floppy emulation mode says “no image files found”, even though there are disk images on the SD card
  • Emu resets to the smiley face screen in the middle of disk I/O, as if you had pressed the reset button

Combo Firmware 0.6A-F14

Once again, if you try this firmware, I would appreciate feedback on what systems you tried it with and what the results were. Thanks!

Read 14 comments and join the conversation 

14 Comments so far

  1. Steve Chamberlin - December 7th, 2014 3:24 pm

    This firmware also introduces a special undocumented feature: by building a custom cable, you can now daisy chain multiple Emus while in HD20 mode, with a single Emu in floppy mode at the end, or a single real floppy drive. See https://68kmla.org/forums/index.php?/topic/21368-floppy-emu-emulating-hd20/?p=253118

  2. Nick Chalau - December 8th, 2014 9:22 am

    So to put programs inside the hd20 all i have to do is attach them in mini vmac ?

  3. Anonymous - December 8th, 2014 10:43 am

    yes 😉

  4. Charles - December 8th, 2014 12:43 pm

    but……… now after this new firmware, all you do is have to toss a bank hd20.dsk image on the SD card and you can initialize it with the mac.

    http://www.gryphel.com/d/minivmac/extras/blanks/blanks-1.0.0.zip

    download this its a whole set of different sized blank image just unzip the one you want… and copy it to your SD card,
    the only thing i am not totally sure of , Does the HD20.dsk still have to be contigious ?

    don’t let me fool you, i have learned everything i know about all this Emu/Image stuff from Steve 🙂

  5. Charles - December 8th, 2014 12:47 pm

    by the way thanks to Thomas from France, The Mac LC-II , just by soldering one wire, Will now boot right from the HD20 emu!

    Also , a little more complicated… but with a HDI20 cable, the HD20emu will also boot the powerbook 100!

  6. Steve Chamberlin - December 8th, 2014 1:05 pm

    Most of the time the HD20.dsk file will end up contiguous anyway. If it’s not you’ll know it, because you’ll see an error message on the Emu screen when it powers up. In that case, just use one of the methods I described earlier to get a contiguous file.

  7. Jason - December 9th, 2014 3:14 pm

    Hello! OK, I’ve got the firmware updated. Creaed an hd20.dsk file of roughly 100MB. Set the Floppy Emu to disk drive mode. Restarted. But I see no drive. The Floppy Emu says

    HD20 DISK EMULATION
    UNTITLED
    96 MB

    What do I need to do to see that drive appear on my Mac (Mac SE/20)?

    Also, I am using a 16GB SD card. Is that the problem? And if not, how can I get an hd20 to be bigger than 96 MB?

    Many thanks everybody…sorry for the beginner questions, but I could not find clear instruction on this, as I suppose it is so new. But what an AWESOME device (um, once I get mine to work!).

    –Jason

  8. Jason - December 9th, 2014 3:17 pm

    [[[SORRY…forgot my email on the last post…posting the question again with that link so your answers so I can be alerted via email if anybody comments. Thanks and sorry!]]]

    Hello! OK, I’ve got the firmware updated. Creaed an hd20.dsk file of roughly 100MB. Set the Floppy Emu to disk drive mode. Restarted. But I see no drive. The Floppy Emu says

    HD20 DISK EMULATION
    UNTITLED
    96 MB

    What do I need to do to see that drive appear on my Mac (Mac SE/20)?

    Also, I am using a 16GB SD card. Is that the problem? And if not, how can I get an hd20 to be bigger than 96 MB?

    Many thanks everybody…sorry for the beginner questions, but I could not find clear instruction on this, as I suppose it is so new. But what an AWESOME device (um, once I get mine to work!).

    –Jason

  9. Thomas - December 9th, 2014 5:28 pm

    Hi Jason,

    What does the real mac tell you about HD20 when you boot it up? (initialize or something like that).

    If It behaves like no other new disk is attached it may simply means your Mac doesn’t support HD20 in hardware…

  10. Thomas - December 9th, 2014 5:34 pm

    What is an SE/20??? To my mind it’s an SE with a 20 MB hard disk drive… (It should recognize the HD20 natively). But if you’re are talking about the SE/30 (a mac IIx/IIcx hardware speaking) it seems normal it doesn’t recognize the HD20!

    The 16Gb card may also affect emulation, althought I didn’t try any SDHC cards with my emu… Ask BMOW about that (my SD card is actually 1Gb with a 20 Mb HD20 image on it) 😉

  11. Steve Chamberlin - December 9th, 2014 5:44 pm

    That’s right, the SE/30 can’t use HD20 disks. The list of compatible Macs was in my first post about HD20 emulation from last week: http://www.bigmessowires.com/2014/11/25/hd20-firmware-0-1/ The Emu’s floppy emulation works on any vintage Mac, but the hard disk emulation is only for vintage Macs with HD20 support.

  12. Jason - December 9th, 2014 6:00 pm

    Ah…makes sense. Should work on my Mac Classic I imagine…I wonder if its 030 accelerator will mess thins up there… great product anyway…a real life saver! I’ll get the SE/30 to connect out via ethernet and all will be swell.

  13. Steve Chamberlin - December 9th, 2014 6:26 pm

    Yup, the Classic should be good with an 030 accelerator. You can also replace the ROM in your SE/30 with a IIsi ROM, then it will have HD20 support. http://www.downtowndougbrown.com/programmable-mac-rom-simms/

  14. techknight - January 7th, 2017 7:08 pm

    I would like to chose different HD20 images like regular floppies do. How do I do this?

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