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Re: CP/M 3 Boot from a Compact Flash - problems and need help.

Hi Thomas,
just noticed something a little odd,
looking at your screen shots of your CF card LBA sector 0 as reported by HxD and the same sector as read by your S100 IDE card there are some discrepancies in the values, for example
mem location         HxD (LBA0)         S100 IDE
00E8H                  6F                       68
00EAH                 6F                        68
0140H                   2F                       68
there may be more,
what CF card are you using and do you have another CF card you can use ?
David Fry

On Wednesday, June 11, 2014 8:35:13 PM UTC+1, Thomas Owen wrote:

Now that I have my IDE card passing all the preliminary tests, I am trying to install CP/M on the Compact Flash drive and get the system to boot.



Compupro ZPU at 2 mhz.

IDE CF Card, version 2.0a

IMSAI SIO for console

Ram 17 with Eprom installed at ‘E000’

8 gb Kingston CF


Have read, and re-read all the articles I can on the site, and decided to use the method put together by David Fry found here.




Step 1 - I modified HLDRBIOS.ASM to support my Console device (IMSAI SIO)


Step 2 - I modified CHARIO3.ASM to support my Console device


Step 3 - Assembled and built the CPMLDR.COM


Step 4 - Copied it to the CF at Sector 0


Step 5 - Assembled and built the CPM3.SYS and copied it to the CF at sector 112


Step 6 - Moved sector 48 to sector 63 on the CF


I know the install is not complete, but at this point I wanted to see what a ‘Boot’ looked like from David’s MYIDEROM:

At boot I see displayed on the console and MYIDEROM reports this drive information:


Cyl:      3C82               Heads:            010                 Sectors:  0048


Then I choose ‘C’ for Boot CP/M and here is where I see a problem:

Notice the ‘LBA = 003C003C’.   Why is that value so high and incorrect?


Any suggestions to getting is completed?


Thanks in advance,