a) The Geneve was created by a third-party company Myarc, and I don't know much about the rights concerning the boot ROM. There has never been a question about it since it was only distributed on board. However, there was an upgrade to enable booting from SCSI drives (Boot ROM version 1.0), and I don't know whether this may be distributed freely.
b) The operating system "MDOS" was sold by Myarc to a group of private people still alive and working on it (see the welcome screen with the year). MDOS is a monolithic OS in a single file called SYSTEM/SYS. The LOAD/SYS file is needed when the HFDC controller is present since it installs a loader for the MFM harddisk. I know that the current maintainer does not agree to publish the sources, but IIRC distributing the compiled file may be OK. I have to ask him.
c) The ROMs and cartridges of the TI-99/4 and /4A are still copyrighted by TI or by third party producers. I heard, however, that TI is willing to grant permission to distribute to anyone explicitly asking for that, provided that no copyright notices are removed.
d) As for the TI-99/8 I remember someone saying that TI granted permission to use, change, and distribute the ROMs to a user group that once asked for permission. (We have the original manuals and source codes from the development people.) Still, I don't know anything about a general permission.
(BTW, you will hardly find anyone at TI who remembers their own home computer. Most of those technicians have already retired.)
e) Everything about the SGCPU (aka TI-99/4P) is copyrighted by the system 99er user group (SNUG), and up to now they object against distributing their works. The policy is that you may only use it if you have their hardware, but maybe this will change in future as there is no more interest in building more SGCPUs.
