Altair-Duino 5MB HD with 1024 directory entries
The "Altair-Duino" has a hard disk simulation that uses a hard disk from Mike Douglas: https://deramp.com/downloads/altair/software/hard_disk/CPM/ The problem with the hard disk image there (HDCPM22v16-48K.DSK) is that it nly supports a very limited (256) number of directory entries. The image here supports 1024 directory entries.
Altair Duino page is: https://adwaterandstir.com/ This is a very nice kit Altair 8800 (blinking lights, speed, etc.). It can simulate floppy and hard disk. This project just patches the hard disk bios to support more directory entries -- sorry, no source, I "hot patched" this.
In Mike Douglas' version of MOVCPMH.COM (everything in hex):
2583 - OPTIONS
10 enable interrupts
01 execute command on cold start
02 execute command on warm start
2584 - default iobyte
2530 - dph for hard disk
2537 -ff 03 ff 00 - allow 1024 directory entries