Maybe built in ndless. No more reinstalling.

What do you mean by this?

When the calculator shuts itself off completely, like you need to boot up again, you must rerun ndless_installer. This also happens wehn you turn off and change pads...

ps firefox is pissing me off... english dictionary isn't installed or something
edit:... some reason the thing was in German...

Ahaha.

That's why we should not force the installation of the OS we want to lauch, but run it over another Ndlessed OS.

When you restart the calc, you'll just have to:
- Ndless the original OS again
- relaunch your "special" OS

If the OS is not compressed/encrypted (TNC/TNO files), you can just launch it directly like any program.

I assume you would still need a modified boot2 to load a modified OS?

Probably not. IIRC, from the files' sizes, RunOS didn't use a modified boot2.

Hot-patching the OS in RAM before launching it seems necessary.

Indeed, many questions :

Launch directly like renaming to .tns and opening as any ndless program, or launch like diagslauncher/boot2launcher by loading into ram and directly executing?

In my view, renaming the pristine .tnc/.tno / the TNOC-shrinked .tnc/.tno / the OS image manually extracted by the user to .tns on the computer before transferring it as a regular file, and launching the "OSLauncher" (Ndless program) .tns.

So all that is really needed to run an OS directly is to decrypt the image?

Probably not just decrypt it.
I'm positive that the decryption can be performed on the calculator, at the cost of increased launching time. In fact, it needs to be for user convenience reasons.

(Does boot2 do that or does the OS do that as it loads?)

The boot2 decrypts the OS, indeed.

If you ran them that way, would you lose the extra files included in the compressed image? (all the /phx stuff (is that folder any different for the CAS and basic nspire?))

I'm not sure, so I'll let others reply to that bit.

Could you obtain a decompressed copy of the OS from nspire_emu as it is running

Yes, but you couldn't distribute it anyway, for legal reasons.

or would you need to look inside boot2?

For on-calc decryption, yes. Two methods were publicly posted in the past, but at least one of them was redacted. Anyway, they involved searching for the Blowfish decryption functions and key, and either using the embedded decryption functions in a generic emulator (whose addresses in the boot2 1.4.x and OS 1.7.2741, 2.0.1.60 and 2.1.0.631 are known, perhaps not publicly though), or a set of Blowfish functions as part of an external program.]

Quote

Hot-patching the OS in RAM before launching it seems necessary.

Are you referring to an uncompressed and unencrypted OS image file launched in the same way as diagslauncher/boot2launcher?

I'm referring to the OS image after decryption, but the OS image could be stored in encrypted form and launched by "OSLauncher".

If so, what functions would need to be patched and why?

No precise idea (i.e. I think I can imagine some reasons, but not give any specifics - at least without looking e.g. at the Ndless source), I'm just reposting what critor wrote elsewhere

And who made RunOS?

geogeo & ExtendeD, AFAICT.


[various EDITs: grammar at one place, and additions.]