Category Archives: news

Moving date has finally arrived!

After a seemingly interminable hiatus punctuated and prolonged by a series of nasty surprises including bereavement, a hand injury, a leaking roof, and a building surveyor who is apparently partially sighted, we are finally moving to our new address on 25 November. Read more here.

U1MB, Incognito, SIDE, SIDE2, SIDE3, 1088XEL and 1088XLD Firmware Update

I’m pleased to release the latest firmware update for the U1MB, SIDE and Incognito platforms. The update includes the following:

  • Unified UI design (compliant with the latest SIDE3 loader)
  • Sophia 2 plugin fix
  • JED version reporting fix
  • New screensavers
  • Various SIDE Loader and SIDE3 Loader bug fixes

The updates may all be downloaded from the Firmware section of the website.

U1MB, Incognito, 1088XEL and 1088XLD Firmware Update

I’m pleased to release the latest firmware update for the U1MB and Incognito platforms. The update – which updates the main BIOS to version 4.05 – fixes the following issues:

  • Idle (screensaver) timer not being reset by non-repeating keystrokes
  • Default message delay when using joystick
  • ‘Restore defaults’ crash
  • Failure to run plugin callbacks aligned on page boundaries
  • Missing plugin calls in Incognito BIOS
  • VBXE plugin no longer resets board (fixes screen glitch on 1088XEL/XLD)

Other changes:

  • Sophia 2 plugin resolution test period extended to 10 seconds
  • Sophia 2 plugin resolution test can be aborted with ESC

In addition, the SIDECFG.XEX tool (for the SIDE/SIDE2 OSS cart ROMs) has been updated and corrected, and UFLASH has been updated to fix a small cosmetic bug when displaying the Incognito ROM contents.


U1MB users should update the ‘Firmware’ slot with the desired 64K firmware file. Incognito users who already applied the 4.0x update may simply apply the ‘IBIOS.ROM’ file, since neither of the other two firmware components (IPBI.ROM and ILOADER.ROM) have changed at all.

Plugins should be re-installed as required following the update.

Get the update from the Firmware section.

U1MB and Incognito Firmware 4.0 Bug Fix

Thanks to Doug_in_NC on Discord, I’ve fixed a small bug in the recently released version 4.0 firmware update for Ultimate 1MB and Incognito which resulted in joystick trigger processing in the BIOS setup menu not working properly. All archives (for U1MB, Incognito, and 1088XEL/XLD) have been updated, and after installing the corrected firmware (dated 060621), your main BIOS revision number will be 4.03. No other changes have been made.

Please visit the Firmware page to obtain the updates as usual.

Thanks Doug!

U1MB/Incognito/SIDE Firmware Update 4.0 Released

I’m pleased to finally release the long-awaited version 4.0 firmware update for the Ultimate 1MB, Incognito, and SIDE hardware. This includes – finally – the official release of the SIDE3-enabled firmware for U1MB. The update brings a redesigned loader and greatly enhanced plugin capabilities, which include support for exciting new hardware like Sophia 2 and PokeyMAX, as well as the aforementioned SIDE3 cartridge.

The complete list of new firmware releases is as follows:

Please let me know of any issues, and above all – Enjoy!


Discontinutation of U1MB plugin and ‘rapidisk.sys’ driver for Rapidus

Earlier this year, I was informed (by Lotharek) that the U1MB/Rapidus compatibility problems (which have blighted many installations for over four years) have been confirmed to be caused by the Rapidus accelerator itself. The specific cause of said compatibility issue – though apparently observed via tech analytics to be Rapidus itself – remains unknown or undisclosed in any detail, but since it exists, and since the attitude of Rapidus developers still appears to be ‘Works here, so everything is fine’, ‘Your U1MB firmware must be to blame’, ‘the U1MB hardware must be to blame’, ‘Your opinion has no crediblity’, or any one of several other repetitive rebuttals, I have decided to withdraw all Rapidus support from the U1MB firmware and driver collection. This includes the ability to activate and deactivate the Rapidus core in software, and the ability (via the RAPIDISK.SYS driver) to double the HDD bandwidth on SIDE2/XEL-CF systems in the presence of the 20MHz 65C816 CPU.

When I first received Rapidus in 2016, I immediately found it puzzling that the issues I could observe on both stock (with SIDE2) and any randomly selected U1MB equipped machine were regarded as difficult or impossible not only to reproduce, but even to entertain. As a competent hardware installer, it was obvious to me that one statistical certainty is that any other European PAL Atari user with a Rapidus, U1MB and half a dozen Atari machines would be able to replicate the issue if an attention span of more than twenty minutes could be maintained. Nevertheless, my inability or unwillingness to ship a single randomly selected machine from my collection to Poland for ‘diagnosis’ was promoted as the single immovable obstruction in the way of actually finding a solution to the problem. Moreover, I was accused of undertaking a smear campaign against the hardware (for which I nevertheless developed software), constantly criticising the device (the installation of which I repeatedly and in great detail documented on video, presumably advertising the product in the process), and of not wanting the problem to be fixed (regardless of the hours of troubleshooting I undertook and stability fixes I tested).

In December 2020, the U1MB hardware or fimware apparently remains a prime suspect (in the eyes of Rapidus developers) as a cause of problems, regardless of the fact issues were observed with both generations of U1MB firmware, and even with or without U1MB present at all. Moreover, while going about my general business of answering operation queries from users of U1MB/Rapidus combos (since I provide software explicitly to support the interaction of both devices), I cannot do so without being harried, contradicted and fact checked by the Rapidus firmware developer (about whose software contributions to Rapidus I do not even have any complaints; indeed, they deserve nothing but praise). I have therefore chosen to entirely wash my hands of Rapidus, and this means withdrawing all U1MB plugins and drivers related to Rapidus operation. Only by doing this can I wholly avoid involvement in any future discussions of the Rapidus hardware, and thus avoid being drawn into tiresome quarrels or being obligated to provide technical support for problems which no-one can clearly identify or fix.

I realise the Rapidus plugin and HDD accelerator were probably of niche interest, so hopefully the deprecation of both will not cause anyone great inconvenience.

Meanwhile, I will no longer be installing Ultimate 1MB and Rapidus in the same machine, since I consider the combination to be problematic and therefore resistant to any level of quality assurance.

Ultimate 1MB, Incognito, SIDE/SIDE2, 1088XEL/XLD firmware update version 3.10 released

I am pleased to announce the release of version 3.10 of the Ultimate 1MB, Incognito and SIDE firmware, incorporating the recently released SpartaDOS X 4.49, and version 4.0 of the SDX ‘soft-driver’ for SIDE, MYIDE, and Colleen. Updated APT Tools and user documentation are also provided.

What’s New?

As well as several minor bug fixes, this release brings with it numerous performance, stability and usability improvements. Some highlights:

  • Loader’s recursive search speed improved by 25 per cent
  • Optional keyboard/joystick acceleration feature in loader speeds up navigation of long directories
  • Long filename extensions now remain on-screen even while filename is scrolling left to right
  • Card hot-swap reliability improved
  • CF card compatibilty improved
  • ATR swap button now works in loader
  • Loader issue with SD/CF adapters fixed
  • Stereo POKEY detection now compatible with SimpleStereo v3
  • ATR swap button can now be disabled on the Incognito
  • Better boot drive handling (fixes issues with some boot loaders run from FAT-hosted ATRs)
  • Improved DCB error checking in PBI BIOS and support for immediate-mode IO
  • XF551 high-speed SIO bug fixed
  • Regression regarding CONFIG.SYS boot drive setting fixed
  • FDISK large volume/disk bug fixed

Please see the changelogs for the main BIOS, PBI BIOS and SIDE Loader for a complete list of changes.

Download the update here.

SDX 4.49

Thanks to DLT, we have the welcome release of SpartaDOS X 4.49. Unfortunately the ROMs hosted on the official SDX site were put together before I released the updated APT tools and SDX soft-drivers. As ever, however, SDX ROMs for all platforms are included in the new firmware release, with the extra tools I like to provide (notably the LSDEV and LSDSK utilities on the CAR: volume). Note the plethora of ATR disk images I provided in prior updates has been done away with; all ROMs for U1MB and Incognito are included on the corresponding ‘FIRMWARE.ATR’ disk image. This makes the preparation of subsequent updates a little less labour intensive.

Please look at the updated README files in the ZIP archives for complete descriptions of the archive contents.

I hope you enjoy the updated firmware and tools, and as always I welcome feedback including bug reports and feature suggestions (although we are rapidly reaching the end of the road when it comes to available code space on the existing hardware). Donations are likewise welcomed and appreciated, although they are by no means obligatory.

Special thanks to Lotharek at for his continued provision of Candle O’Sin’s fabulous U1MB, SIDE2 and Incognito devices, and for offering my firmware pre-installed at the point of sale. Please continue to support his invaluable efforts.