The ACA500plus features an 8MByte flash ROM with a rich set of software: The menu system, Kickstart ROMs, Action Replay ROMs, HRTmon, and the OS3.1 install files. On this page, you will mainly find software updates for the menu system, but also recovery files for other parts of the flash ROM.
The menu update file is provided as zip archive, because you will most likely unpack it on a Windows-, Linux-, or Mac-PC. Unpack the archive to the root directory of a PC-formatted CF card.
Download: Menu system V0.97
Insert that card into the AUX slot of your ACA500plus, then launch the menu. Press F8 and F to launch the flasher, which will read the update file from the AUX card. Follow the instructions on screen to install the update. If something does not work right away, you may need to reset the computer to launch the flash process.
The unpacked file is an ADF image that can also be written to a floppy disk. You will only need to do this if the flash ROM has been garbled - in that case, the bootable floppy will serve as a recovery-disk.
This is an update that you will only need once in order to use HRTmon with any version of the menu system that you install *after* the delivery version. The actual HRTmon remains the same (and will never be overwritten with a menu software update), but the checksum and header are adapted to what the new menu system software expects. This update can ONLY be used with the flash updater from the menu. It cannot be written as ADF to a recovery disk, despite its file name.