A numworks launcher that let you switch between userland in slot A and B

VID_20260824_012348.mp4.2.mp4

Install the app

To install this app, you'll need to:

1. Download the ABLauncher.nwa file, which you can download from the Releases.
2. Connect your NumWorks calculator to your computer using a USB cable.
3. Head to my.numworks.com/apps to send the nwa file on your calculator.

How to use the app

Key	Action
EXE	Switch userland slot
Back	Quit

Caution

After going back from userland B to A, it will crash by pressing HOME, just so you know ;)

Docs

The app works by changing the stack pointer and jumping to the correct address:

"ldrd r3, r2, [r0] \n"  // r3 = stack pointer, r2 = start address
"msr  MSP, r3      \n"  // set stack pointer
"bx   r2           \n"  // jump to start address

Slot B:

// 0x90400000 : start of slot B
// 0x10000    : userland header size
// 0x30       : slot info size
// 0x90410030 : target address

Slot A:

// 0x90000000 : start of slot A
// 0x20000    : userland headersize
// 0x30       : slot info size
// 0x90020030 : target address

It detects the slot your on:

unsigned long here = (unsigned long)&current_slot;

if (here >= SLOT_A_START && here < SLOT_A_START + SLOT_SIZE) return SLOT_A;
if (here >= SLOT_B_START && here < SLOT_B_START + SLOT_SIZE) return SLOT_B;

See more at: https://nwagyu.org/reference/firmware/slots.html

Build the app

I made tutorials here :

• C-App-Guide-for-Numworks