9.2 allows autoboot. 4.x allows ds profile exploit. Your choice, both work without internet.
9.2 also allows DS profile exploit with downgraded MSET.
9.2 is better than 4.5 since months.
Read the rxtools tutorial thread, it answers all these questions. https://gbatemp.net/threads/tutorial-installing-rxtools-custom-firmware-3ds-and-2ds.390867/Autoboot don't work for me but i have other questions how can i update emunand ,can i install cia files and can i keep my cfw? Thanks
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How can i downgrade mset?
Old 3ds/xl/2ds yes, new 3ds/xl no.Thanks it worked but is safe to update emunand to 10.3? i have RX-Tools.
For menuhax: go on every entry point game in sysnand to go on *hax 2.5 (sysnand is 9.2 and *hax 2.5 works on 9.2 I used ninjhax) and from there you install menuhax (install -> configure -> type 2 (i selected the L button) shutdown 3ds. Now you use the ctrboot datas. (Boot.3ds to boothbl.3ds and put the boot.3ds and boot.cfg from ctrboot zip on the root by the sd card. Start 3ds and you will automatically boot to emunand. If you on start hold L button (or what button do you choose) you come up to sysnand. Its easier to install as you think