Oberon RTK

Build and Load: RP2350

Building and loading programs on the RP2350.

Overview

This document describes how to build, load, and run RTK-based programs for the RP2350 for two scenarios:

  • simple loading, without debugger
  • with debugger

If no debugging is required, UF2 or ELF files can be used; to include DWARF debug data, ELF files are the only option. We'll explain both below.

Note that also without debugging, ELF files can be used for loading. If intended for loading only, you can omit the option --debug when running make-elf. However, it does not hurt if debug data are included in a load-only file, they just increase the load file size. The executable binaries are 100% the same with or without debug data, and consequently there is no "debug overhead" with debug data included.

For programs with Secure/Non-secure segregation refer to Build and Load: RP2350 (S/NS).

See also Practical Notes.

Project Set-up

  • Address ranges: see Build RTK-based Programs.

  • In particular, please pay attention to the section about IMAGE_DEF.

  • For debugging, the additional tools must be installed and configured:

Build and Load, no Debugging

Build the Program

1. Build the program

2. Make the UF2 file

> python -m make-uf2 rp2350 <program>.bin

Notes:

  • alternatively use the UF2 file produced by Astrobe, paying attention to the IMAGE_DEF section;

  • an ELF file made with make-elf --image-def (without --debug) could also be loaded, with picotool.

Load the Image

3. Put the RP2350 in BOOTSEL mode, which mounts the virtual volume RP2350

4. Load the UF2 file to the RP2350

  • Without a partition table, use one of these options:

    • use Astrobe's Run => Upload menu command

    • copy in the Windows File Explorer or the macOS Finder by drag-and-drop to RP2350;

    • copy from the command line using the OS file copy commands to RP2350;

    • use picotool as shown below

  • With a partition table (assuming one partition is of type rp2350-arm-s):

    • use picotool
> picotool load <program>.uf2 -v -x

Notes:

  • copying the UF2 file to volume RP2350 with a partition table does not appear to work, but this could be a defect that is rectified by the time you read this

  • if the target partition is not of type rp2350-arm-s, use option -p <partition-no>

Build and Load for Debugging

Build the Program

1. Build: as above

2. Run gen-rdb to create an .alst file for each module in the program, plus _startup.alst for the startup sequence inserted by the linker at the end of the program; make-elf requires the .alst files to create symbols and DWARF debug data:

> python -m gen-rdb <program>.map

3. Make the ELF file

> python -m make-elf <program>.bin --debug --image-def

Notes:

  • both gen-rdb and make-elf use configuration data from the program's map file in this simple one-binary case

  • by default, the .alst files are created in directory rdb in the project directory

Load the Image

4. Load the debug ELF file to the RP2350

  • Refer to Debugging:

    • GUI: Cortex-Debug inside VisualStudio Code
    • command line: OpenOCD and GDB
    • be aware that loading an ELF file via debugger will overwrite any partition table
    • hence, follow the attach instructions with a partition table

  • Without partition table:

    • use the load debug scenarios in the debuggers

  • With partition table (assuming one partition is of type rp2350-arm-s):

    • put the RP2350 in BOOTSEL mode, which mounts the virtual volume RP2350
    • then use picotool as outlined below
    • use the attach debug scenarios in the debuggers
> picotool load <program>.elf -v -x

Note: if the target partition is not of type rp2350-arm-s, use option -p <partition-no>

Partition Targeting

Any partition can be targeted independent of its type, eg. partition 0:

> picotool load -p 0 <program>.elf -v -x

Tools

Examples (Repository)

  • <repo-root>/examples/v3.1/rpi/pico2/SignalSync
  • <repo-root>/examples/v3.1/rpi/pico2/K4base

Last updated: 17 April 2026