Finaly after a long, long time of research I was able to force booting my own autoexec.bat and config.sys. It seems that other system files similiar to msdos.sys and io.sys are used as built-ins (they aren't on disk A:) and are booted in other way.
I used an autoexec.bat which launched enter.com (my prog) instead of "launcher", then I used maxmem to check free mem and results are *GREAT*:
Normal boot: 58608 free
My boot: 73216 free!
A funny side effect: it seems that launtsr.exe (normally executed by launcher.exe) hooks some routines to keyboard, like SHIFT+AC for power off, so not using launtsr.exe saves some memory but disables power off switch (ofcourse opwer off can be done by a special (simple) program).
How it works (just a sketch, later I'll do a prog for it)
1. sending a desired system disk for booting to one flash disk: L-Q.
2. sending a specially prepared patched boot routine
3. do some segment/drive mapping
4. jumping to the boot code (setting CS:IP)
viola!
Now some drawbacks:
1. this method consumes at least 2 flash drives (maybe it would be limited to 1 if reboot after system transfer to drive A: would use this patched reboot code)
2. this method is probably very hardware dependent (as I own AFX ROM1.01 I have a patch only for this version)
3. after power off and power on calc will probably boot in the normal way (not tested, walkaround - power on using

![[AC/on]](/dot/public/style_emoticons/default/AC-ON.jpg)
Purpose:
1. significant increase of memory available to programmers
2. getting rid of LAUNCHER.EXE and switching to your own file explorer (got to investigate "SHELL" cammand in config.sys)
3. boot what you like
REQUEST
To make this method portable to other AFX ROM versions (like 1.03) I need someone to send me:
1. few first segments of calc's ROM memory (first 5*64Kb should be enough), please send me a note about calc's model and ROM version too (use comsend by BradN or probably GComm can do it) just make sure you send me ROM not RAM!
2. first disk drive (you can use FlashCOM for it - send me your .csf disk).
Roeoender.
Ps. Please don't post anything worthless below.