We have released an important update to the build tools, necessary for compiling OZ V4.7 and development version of OZ V5.0. Find release notes and download links here:

Hi Everyone, we now provide automated builds of OZ ROM from /develop and /master branches, freshly generated per commit, see here:

The pre-made ROM binaries are archived in Zip files, containing ROM images for both slot 0 and 1. You no longer need to install Z88 Assembler Workbench build tools to get installable bleeding edge OZ ROM binaries!

These Zip files contains mostly developer snapshot and pre-releases. They are not considered public releases. Use them for testing and feedback to the development team.

The following ROM releases are available:

ozrom-master-<commitid>.zip (public stable releases, V4.7 and later)
ozrom-develop-<commitid>.zip (stable development builds, V5.0 and later)
ozrom-xxxxxx-<commitid>.zip (bleeding edge testing builds, V5.0 and later)

Unzip any selected archive and you will find the following structure of files (example):

oz.bin              ozs0-fde21e8.44     ozs1-fde21e8.53
oz.epr              ozs0-fde21e8.45     ozs1-fde21e8.54
ozs0-fde21e8.32     ozs0-fde21e8.46     ozs1-fde21e8.55
ozs0-fde21e8.33     ozs0-fde21e8.48     ozs1-fde21e8.56
ozs0-fde21e8.34     ozs0-fde21e8.49     ozs1-fde21e8.57
ozs0-fde21e8.35     ozs0-fde21e8.63     ozs1-fde21e8.58
ozs0-fde21e8.36     ozs0-fde21e8.upd    ozs1-fde21e8.59
ozs0-fde21e8.37     ozs1-fde21e8.32     ozs1-fde21e8.60
ozs0-fde21e8.38     ozs1-fde21e8.33     ozs1-fde21e8.61
ozs0-fde21e8.39     ozs1-fde21e8.47     ozs1-fde21e8.62
ozs0-fde21e8.40     ozs1-fde21e8.48     ozs1-fde21e8.63
ozs0-fde21e8.41     ozs1-fde21e8.50     ozs1-fde21e8.upd
ozs0-fde21e8.42     ozs1-fde21e8.51
ozs0-fde21e8.43     ozs1-fde21e8.52

oz.bin and oz.epr for OZvm emulator

Use oz.bin to load a ROM image in slot 0. Use oz.epr when you want to insert a 1Mb Flash or Hybrid card in slot 1.

ozs0-xxxx-.upd and ozs1-xxxx-.upd files

Installation procedure for slot 0 or slot 1 (Cambridge Z88 with slot 0 using AMD 512K FLASH as ROM). Follow these steps:

OZ V4.7 or later must be running in slot 0 or slot 1 on your Cambridge Z88.

  1. unzip files on your desktop computer.
  2. Make sure that the Panel Default Device points to expanded RAM, typically :RAM.1
  3. Upload all the binaries ozs0-XXXX.* files to default RAM on your Z88, using EasyLink2
  4. Put fresh batteries in your Z88 or use mains adapter when updating slot 0 ROM or flash card in slot 1
  5. From the INDEX execute the <>UPD command, it will automatically find the ozs0-XXXXX.upd file
  6. All binaries are CRC-32 checked and an AMD 512K chip is found in slot 0 or slot 1.
  7. The Screen is turned off. Wait with patience for approx 1min. The Z88 will soft reset and boot
  8. A popup and a bleep will display the updated OZ ROM commit release ID is displayed for slot 0 or slot 1.
  9. Issue a hard reset and your Z88 is now running latest OZ from slot 0 or 1!

Using RomUpdate.bas

If you are running an older OZ ROM (OZ V4.6 or earlier) in slot 1 and have and earlier OZ in slot 1 on a flash card, use romupdate.bas on your Z88 (download this archive utility.

  1. Remove OZ ROM Card from slot 1, to slot 3, have expanded RAM in slot 1 or slot 0. Make sure that the Panel Default Device points to expanded RAM, typically :RAM.1
  2. Rename ozs0-xxxx.upd or ozs1-xxxx.upd to romupdate.cfg, and upload all related bank files to Z88, then:
  3. From the FILER execute the romupdate.cli file with <>EX command. The program will instruct what to do.
  4. The OZ card is then flashed in slot 3
  5. After ROMupdate has completed put flash card in slot 1 and RAM card in slot 2 (if you have one).
  6. Hard reset your Z88.

Now your Z88 is running latest OZ ROM either from slot 0 or slot 1!

Enjoy. 😊

ZEsarUX 6.0 stable


ZEsarUX 6.0 stable is out! This is a major version, it includes some new machines and a lot of new features and bug fixes

You can download it from the usual URL:

I hope you like it!


Version 6.0. 27 November 2017 - Gunfright edition

Added machine ZX-Evolution TS-Conf
Added machine Chrome (Italian ZX Spectrum Clone)
Added machine MK14
Added lots of new ZEsarUX remote commands (ZRCP). See ZRCP help to know them
Added Visualmem, Poke, Find, Save binary menus also for Sinclair QL
Added QL GUI Style
Added setting to test configuration
Added menu to find and set lives in games
Added menu to view color palettes
Added actions commands to breakpoints, so you can run some actions when a breakpoint is fired
Added up to three AY Chips
Added emulation of other DAC chips appart from Specdrum: Covox, etc
Added Antonio Villena's "Kartusho" cartridge interface
Added quicksave function
Added setting to set 256kb or 512kb on Spectrum 128k machines
Added setting to set F keys (F1, F2, etc) to run different actions: reset, nmi, exit emulator, etc
Added TBBlue features: Sprite chip, Layer2, RTC clock for esxdos, 2 MB RAM, new 8kb block MMU, 9-bit palette, lores mode, layer priorities, partial Next Z80 opcodes (see extras/docs/tbblue/new_opcodes.txt to know which are emulated)
Added ZX-Uno features: Radasoffset and Radaspadding registers, to do hardware scrolling
Added ESXDOS handler so file operations can be done with files stored on your computer hard disk, and not only on virtual mmc/ide files. Examples can be found on extras/media/spectrum/esxdos_handler/. "Classic" mmc/ide emulation by using virtual mmc/ide files can also be used
Added feature "memory zone" to ZRCP and all menus that inspect memory (debug, disassemble, sprites etc): now you can look at all memory zones, for example: full 128kb ram, 64kb rom of +2A, divmmc ram, etc
Added file utils menu, to view files, delete, truncate, etc
Added boot logo
Added setting to allow to load a .sna snapshot file without changing the current machine type
Added setting to allow to truncate a tape file when selecting it as tape out file

Moved folders: docs, media, snap_tests to a "ZEsarUX-extras" package. These folders have been separated from the emulator main distributed file, and the main download have been reduced to 5 MB aprox. The git repository still holds all the files (extras have been moved to folder "extras"), but maybe in the future I will remove them also from the repo.
Moved mmc/ide files location to extras/media/disk_images folder

Improved menu interface:
*menu gui is zoomed when running following machines: QL, TSConf, CPC, Prism, Sam
*menu movement with mouse
*colours are greyscaled when multitask disabled
*allow blinking text, like the input cursor (needs multitask on)
*new splash window type which disappears automatically (needs multitask on). Used only on change memory zones from debug cpu menu, but it will be used on more places probably

Improved debugger:
*you can now set conditions for all flags, written as: FS,FZ,FP,FV,FH,FN,FC
*now you can set breakpoints from command line/config file but not enabled by default. You need --enable-breakpoints setting
*now the multitask setting is not lost when a breakpoint is fired
*now you can repeat last command by pressing enter on ZRCP (requires enabling a debug-setting)

Improved QL emulation: experimental support of LBYTES command, added QL root directory selector for mdv1, mdv2, flp1
Improved Sprite Viewer: Save sprite, TBBlue sprite viewer, inverse sprite, set bpp (8,4,2,1), set palette
Improved stdout driver. Now can show ansi colours
Improved messages windows. Can now find text using f and n
Improved footer. Host CPU % usage on footer is not enabled by default to avoid confussion with emulated CPU speed. You can enable it with a setting. Host CPU % usage is not shown on Windows.
Improved Visual Mem:
*showing also read memory and opcode execution visual mem
*it has a counter (0-255) to see how many times an address has been read/executed
*menu draws different values as red tones, with a configurable bright

Fixed turbo mode and breakpoints. Breakpoints were disabled when changing turbo mode
Fixed latency problems on all audio drivers
Fixed AY sound bugs when volume levels where > 15
Fixed Windows pthreads version
Fixed TBBlue reset i/o ports when reset and hard reset
Fixed Windows freeze issues when doing cpu-step on ZRCP

Updated TBBlue boot loader

Some other minor bugfixes and improvements


We're on Telegram

We have created a public Telegram chat room for everybody interested in Cambridge Z88 news, releases, bug reports and general discussions.  Use this link, The public group name is @cambridgez88.

It's been a long time coming. Finally the complete OZ ROM and Z88 application builder tools are available in latest edition, 2017.4. This release supports building OZ V4.7 ROM and newer source code releases. We have also added Arm7 as distribution platform as for Linux Chromebook and myriad of Arm-based tinker boards such as the Raspberry Pi2/3. Installers are available for Windows, Linux and MacOS for Intel 32/64 bit platforms.

Release notes & downloads can be found here: Z88 Assembler Workbench 2017.4 Release Notes

New ZEsarUX 5.0

Hi. I have released a new version of my emulator ZEsarUX. 

Finally I have succeded emulating Sinclair QL. I dedicated a lot of hours trying to guess how the keyboard work.
There is little documentation and I had to do lots of dissassemblies of the ROM and testing keyboard to know how it work...
So, hard work, this is a Quantum Leap, so this is a new major version, 5.0!

I will only post here changes related to Z88 or to the whole emulator, excluding other machines like Spectrum, etc.

You can also read the full Changelog here:

So, this is the short change log:

Added Sinclair QL emulation
Added remote command protocol. You can do enhanced debugging on ZEsarUX by using a telnet client.
There are a lot of commands, even many commands exclusive to this protocol and not found on the GUI, like:
* load-source-code
* hexdump-internal
* set-register

Added Easter Egg ;)
Added setting to write configuration file
Added autosave snapshot at fixed interval
Added File Viewer
Added support for drag&drop on Mac OS X, SDL2
Added support for OpenGL rendering on Mac OS X Cocoa driver
Added Man Software GUI Style
Added setting to disable autoframeskip
Added setting to set breakpoints from command line
Improved Debug CPU Window: now you can switch between different views:
1) 1 opcode, cpu registers, other internal registers
2) 9 opcodes, other internal registers
3) 15 opcodes
4) 9 hexdump lines, other internal registers
5) 15 hexdump lines
Fixed text to speech routine when sending non-ascii character
Fixed bug mapping real joystick buttons and axes with same number
Updated Z88 OZ V4.7
Some other minor bugfixes and improvements



Project hosting of the Z88 Assembler Workbench tools, OZvm and EasyLink2 are now hosted on and Release of latest binaries of assembler tools OZ on all platforms follows in a couple of weeks, to be announced here.

OZvm V1.2 released

More than two years of major changes and improvements have gone into this release, while developing several OZ ROM releases. We now can support a native-compiled application on all major desktop platforms. Read the release notes for more details.

OZ V4.7 ROM released

We're proud to announce our latest ROM release for the Cambridge Z88, V4.7; contains new features and lots of improvements. Release notes and download links HERE


I have uploaded a new version of ZEsarUX emulator.

You can download it from the project web page:

This release comes with a lot of changes, you can see the full changelog here:

The following are the Z88 and general related changes:

Version 4.2. 5 December 2016 - Rescue on Fractalus edition

Added Z88 Hybdrid (RAM+Eprom) Card support

Added Sam Coupe GUI Style

Added Z88 generic card browser

Added Z88 card browser when copying from eprom/flash card

Fixed Z80 cold start registers

Fixed Z88 bug when smart loading all slots were ejected

Fixed handling symbols (.  , : / - + < > = ' ( ) ") on menu for machines: Z88, CPC, Sam Coupe

Fixed enabling some memory and debug interfaces, so you can enable and disable them in any order you want

Fixed drawing of some menu items that refresh continuously: waveform, ay registers, cpu stats, debug cpu, visualmem

Improved menu. Now all settings are on a separate "Settings" menu

Improved debugger:

*Individual breakpoints can be disabled

*Breakpoints are fired by default when condition changes from false to true. And they are only fired again when condition changes from true to false and false to true

Improved windows with text content. Now a progress symbol (*) is shown

Updated Z88 OZ V4.6.2

Some other minor bugfixes and improvements

I hope you like it (smile)



Z88 FPGA running!

With the help of Frederic, a complete rewrite of the Z88 FPGA Verilog implementation has been done. The machine works beautifully at 6.125 MHz on a DE1 board (old Cyclone II FPGA). OZ is entering a new era...


I have uploaded a new stable version of my emulator ZEsarUX 4.1

You can download it from the project page:

This version adds two new machines: Sam Coupe and TBBlue/ZX Spectrum Next

Other important changes:

-Added DivIDE emulation
-Added tape loading at max speed
-Added turbo modes: native support for ZX-Uno, Prism, Chloe and TBBlue, and manual for other machines
-Added menu themes
-Improved debugger with new features: t-states partial counter, breakpoints on reading/writing port/memory
-Added On Screen keyboard, useful when using joystick

To view the full changelog:

I hope you like



Full description of OZ localization is described in Developers Notes. All ISO, key and fonts tables are detailed. Notice that OS_Nq / Nq_Rds has been upgraded to full ISO compliance. It allows usage of ISO characters in filing system.


The tools necessary for compiling Cambridge Z88 software have finally been released as ready-made installers for all major desktop platforms. For many years, these tools were work-in-progress development alongside the evolution of the Z88 ROM sources and 3rd party applications. Often, internal releases were distributed directly among developers, when the latest and greatest feature were ready.

No more.

Finally, both Mpm - the Z80 macro assembler - and Z88card - a binary file card manager tool for generating Z88 ROM and application card images, are ready for public use.

These tools combined together form the Z88 Assembler workbench, which is used to both compile the Cambridge Z88 ROM and a good bunch of 3rd party Z88 applications (FlashStore, EazyLink, ZipUtils, etc).

Installers are available for Linux 32/64bit, Windows 32/64bit and Max OSX (64bit), from SourceForge File Area:

We have also produced a step-by-step guide video that explains the process of installing the tools, downloading latest OZ source code, compiling it and installed into the OZvm emulator, for your viewing pleasure: