The firmware & hardware has been extensively revised to better suit the Atari ST range of computers. The PCB has been revised in various places to include more parts on the bottom so that they can be supplied preassembled. It's most prominent new feature is the on-board DUALTOS ROM where the decoding is built into the PLD. You can for example have TOS206 and EMUTOS in ROM without requiring a separate dual TOS board. There have been other tweaks for better compatibility with the Atari machines such as fixing the IDE port to use a standard cable.

NOTE: Only 60MB of TTram is available as some is used for ROM shadow. Typically 60MB is free to use, the next 1MB is a "black hole" to prevent TOS from declaring it. Then ROM area and special registers. RAM could be used above that in special software but probably nothing will use it.

CURRENT20 288XL FIRMARE STE536 / ST536 - October 26, 2025 - Latest "stable"
CURRENT21 - Non-inverted SDRAM clock - test firmware
CURRENT21I - Inverted SDRAM clock - test firmware
CURRENT22 - CP=11, BG fix - test firmware

OTHER STUFF

EMUTOS1.4_TOS206 DUALTOS ROM - (Patched 206) October 26, 2025

Day of the tentacle (GAME)

BLTFIX1.2 - Needed in AUTO folder to fix blitter issues.

ROM SPACER - Keeps pressure on the STE536 from the top metal sheilding.

BRACKET - Adds support for the rear of the STE536.

JTAG - PLD programming header.
CDIS - CPU Cache disable (generally not used)
MMUDIS - CPU MMU disable (generally not used)

ROM HEADER:
BANK 0 - Lower ROM bank select
BANK 1 - Upper ROM bank select
512K ROM - Can use 512K OS ROM (currently not used)

JP2 - 5V power input direct from PSU - Currently with a quality PSU I have not seen any reason to connect the powre directly.

SJ3 - Middle and bottom pad must be connected to enable the default OSC.

Any other jumpers or solder pads are not to be used or connected.

REV4.7D IC10 Regulator may be missing. It was a upgraded regulator from previous builds. Part number ADM7172ACPZ-3.3-R7 / GM12046ACPZ-3.3-R7