Patch for Fuzix v0.3 to run on real TRS-80 Model 4(p), with FreHD autoboot

This is a patch to address 2 bugs in the official distribution of Fuzix release 0.3 for the TRS-80 Model 4-4p, to allow Fuzix to run on real hardware.

The first bug is a bad initialization of the CRT controller, causing the 2 1K video pages to be swapped.

The second bug is a missing wait ready loop after the OTIR statement used to write bytes to the hard disk.

Another change is the addition of a hard disk loader, to load the bootloader originally stored in the floppy image trs80-0.3.jv3, directly from an additional cylinder on the hard disk. The modified hard disk image is directly bootable from the Model 4p without needing the replacement of the original ROM with the special FreHD Boot ROM. It's also compatible with the special FreHD Boot ROM on both the Model 4 and the Model 4p.

• First, download and decompress the original Fuzix floppy and hard disk images https://www.fuzix.org/downloads/0.3/trs80-0.3.jv3.gz and https://www.fuzix.org/downloads/0.3/trs80-0.3.hd.gz . This can be done by running the scriot getfuzix.sh.

• Download ZMAC from https://48k.ca/zmac.zip . This will be used to build the new Hard Disk boot sector from trs80-0.3.hdboot.asm and the patched Fuzix system core from trs80-0.3.sys.asm.

• Build the utilities HardDisk.exe, JV3Disk.exe and Patch.exe from the C source files, using Visual Studio and the scripts mk_HardDisk.exe, mk_JV3Disk.exe and mk_Patch.exe. It may be necessary to adapt vcvars32.bat for your particular installation of Visual Studio.

• Run make_trs80-0.3.hdboot.bat to build the new hard disk image, with the new boot sector, the boot loader extracted from trs80-0.3.jv3 and the patched system core from trs80-0.3.hd. This creates a new hard disk image fuzix003 which can be directly copied to the FreHD SD Card.

To run the new Fuzix system in TRS80gp:

• Download TRS80gp from https://48k.ca/trs80gp.html or by running the script gettrs80gp.sh.

• Run TRS80gp with the new hard disk image with trs80gp_Fuzix_HD_HDBoot.bat or by running the following command: windows\trs80gp.exe -m4p -h0 fuzix003

Enjoy !