========================================================================================== tiosmod - a computer-based unlocking and optimizing program aimed at official TI-68k calculators OS Copyright (C) 2010, 2020 Lionel Debroux - TICT (lionel underscore debroux yahoo fr) Copyright (C) 2020 RANDY Compton Portions Copyright (C) 2000-2010 Olivier Armand

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Author's motivations

By chronological order of appearance: optimizing, unlocking, and fixing.

• the initial motivation of this work was scratching a very old itch of mine (before the creation of FreeFlash): modding TI's OS to optimize several hunks of code that have bothered me for more than six years.
• the motivation to remove TI's silly protections, while at it, came later, as a consequence of TI's increasingly frequent and increasingly vicious attacks on our freedom to tinker with the devices we own...
• the motivation to fix bugs was not present either when I first thought of fiddling with the OS, but it's a logical consequence of TI abandoning the TI-68k line years ago:
  • the la(te)st OS upgrade for 89T and V200, AMS v3.10, was released in July 2005;
  • the la(te)st OS upgrade for 89 and 92+, AMS v2.09, was released in March 2003 (and AMS 2.08 & 2.09 for 89 use the 0x340000-0x34FFFF sector, depriving users from 10% of the archive memory they could use on earlier 2.xx versions...). It's high time we programmers/users tackled the tasks that the manufacturer is no longer doing ! And now that we have factored, in the summer of 2009, all interesting public RSA signing keys used in TI-68k and TI-Z80 calculators, we don't even have to use FSign + FreeFlash, or the older TIB-Receiver, any longer :-)

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Usage information

• Users just interested in using patched AMS versions should use the provided binary diffs. Currently, four formats are provided: xdelta 1.x, xdelta 3.x, bsdiff 4.x, ips. For all of those formats, there's at least one no-fee program that can handle them, and some of these programs are open source. For more information, see the usage help printed by each program. NOTE: the binary diffs provided along with the official distribution perform all changes that the patchset knows how to perform, including: * hard-coding the standard font (it will hardly make a difference to anyone, since the possibility of redefining fonts is virtually unused); * hard-coding the English language (it will make a difference to more users, since it interferes with language localizations).

• Programmers interested in tinkering with the patcher / patchsets, who know wha they're doing, can figure out how to compile the program by themselves ;-) See http://www.ticalc.org/archives/news/articles/14/145/145273.html for links to RabbitSign and FSign+FreeFlash, the former being preferred nowadays because it's more convenient.

Standard warranty disclaimer: you're on your own if you mess up calculators by using pristine or modified versions of the patcher & patchset(s).

Please also note that redistributing ready-made, modified versions of TI's copyrighted OS is illegal in most countries ;-)

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Changelog

v0.2.7: * supported AMS versions: no change. * new fixing capabilities: * revert AMS 3.10 to the 0^0=1 behaviour of older versions. Patch and 89T test by RANDY Compton, (emulated) V200 test by myself.

v0.2.6: posted on Cemetech, Omnimaga, TI-Bank and yAronet on 20101024. * supported AMS versions: no change. * bugfixes: add an fseek to SearchBackwards* building blocks of tiosmod.c; * new fixing capabilities: * fix the bug that can occur when changing batteries (HW3Patch does it). * improvements: * the program can now be compiled under Windows as well: msvcrt offers fileno + truncate, only called differently. Add explicit Seek() or internal fseek() before using Write* or Search* - it doesn't seem to be necessary on *nix, but seems to be on Wine (at least).

Uploaded to ticalc.org on 20101017.

v0.2.5: posted on Cemetech, Omnimaga and TI-Bank on 20101017. * supported AMS versions: 2.05, 2.08, 2.09, 3.01, 3.10 for all models. * improvements: * the Flash memory execution protection is now, hopefully, disabled on HW1 calculators as well. Spotted by Kevin Kofler. * new enhancement capabilities: * add back OSVRegisterTimer/OSVFreeTimer + handling code in the AUTO_INT_5 handler and in the timer initialization code, removed by TI in AMS 2.04. Ultimately, what makes this easy enough is the fact that while the code was removed by TI, the storage area (2*12 bytes) in RAM was not: it remains reserved and accessible through trap #9.

v0.2.4: posted on Cemetech, Omnimaga and TI-Bank on 20100925. * supported AMS versions: 2.05, 2.08, 2.09, 3.01, 3.10 for all models. * moved more AMS-specific functions from tiosmod.c to amspatch.c. * improvements: * checking the OS upgrade's size is now done through an exact match where possible; * after finding copies in TI-Connect 1.2, AMS 2.08 for 92+ and V200 have now been tested on emulator and are officially supported; * new fixing capabilities: * fix OSContrastUp/OSContrastDn not to destroy d3 and d4 (bug #53 of http://www.technicalc.org/buglist/bugs.pdf).

v0.2.3b: posted on Cemetech, Omnimaga and TI-Bank on 20100922. * supported AMS versions: no change. * new fixing/enhancement capabilities: * replace buggy AMS trap #3 (wired to OSenqueue, which doesn't work for two reasons) by UniOS/PreOS-style HeapDeref. Suggested by "Folco" Martial Demolins.

v0.2.3a: posted on Cemetech, Omnimaga and TI-Bank on 20100916. * supported AMS versions: no change. * bugfix: typo in the shrinking code for AMS 2.09 for 89 caused incorrect patching, yielding crash-producing memory corruption, when tracing functions or plots in the graph screen. * improvements: * reject AMS 2.08 for 92+ and V200 until they have actually been tested (although the current patching code is expected to work, since the AMS 2.08 and AMS 2.09 binaries are very close to each other). * add and print a patch description below the program's name & version.

Github repository http://github.com/debrouxl/tiosmod created on 20100915.

v0.2.3: posted on Cemetech, Omnimaga and TI-Bank on 20100914. * supported AMS versions: 2.05, 2.09, 3.01, 3.10 (all models), 2.08 (89 only for now, I don't have copies of 2.08 for 92+ and for V200 - but the patching code may work on those as well, seeing that 2.08 and 2.09 are very close to each other). * new shrinking capabilities: * EXPERIMENTAL: shrink AMS 2.09 for 89, so as to make it fit in the same number of sectors as AMS 2.01-2.05 :-) (USE AT YOUR OWN RISK - only lightly tested !)

v0.2.2: posted on Cemetech, Omnimaga and TI-Bank on 20100914. * supported AMS versions: 2.05, 2.09, 3.01, 3.10 (all models), 2.08 (89 only for now, I don't have copies of 2.08 for 92+ and for V200 - but the patching code may work on those as well, seeing that 2.08 and 2.09 are very close to each other). * split the program into the building blocks for making a patch (tiosmod.c, under GPLv2) and the patch itself (amspatch.c, under WTFPLv2). * new capabilities: shrinking: * EXPERIMENTAL: shrink AMS 2.08 for 89, so as to make it fit in the same number of sectors as AMS 2.01-2.05 :-) (USE AT YOUR OWN RISK - though AFAICT, my testing 89 runs the modified version just fine) * now distributing binary diffs suitable for xdelta 1.x, xdelta 3.x and bsdiff.

v0.2.1: posted on Cemetech, Omnimaga and TI-Bank on 20100822. * supported AMS versions: 2.05, 2.09, 3.01, 3.10 (all models). * new unlocking capabilities: * remove artificial limitation of the size of ASM programs on AMS 2.xx; * remove "Invalid Program Reference" error, artificial limitation of AMS 2.xx and later when using ASM programs in expressions.

v0.2: posted on Cemetech, Omnimaga and TI-Bank on 20100813. * supported AMS versions: 2.05, 2.09, 3.01, 3.10 (all models). * now named "tiosfix", todo/wish list expanded. * tiosfix now checks and updates the AMS ("basecode") checksum. * new optimization capabilities: * OPTIONALLY hard-code English language in XR_stringPtr. After this, language localizations don't quite work properly... They have always been a half-baked thing anyway (many TI-BASIC programs work for English only, it's insanely hard to use a number of TI-BASIC functions in such a way that the program is portable across all locales), and they make XR_stringPtr (used, besides the GUI, in the parsing) more than an order of magnitude slower.

v0.1: first public release, posted on #ti on 20100717. * supported AMS versions: 2.05, 2.09, 3.01, 3.10 (all models). * new unlocking capabilities: * skip FlashApp signature validation (Flashappy);

v0.0: sent privately to several persons. * supported AMS versions: 2.05, 2.09 (89 / 92+). * unlocking capabiliti