#Storage

RMK's storage system provides persistent flash memory for storing data like keyboard configurations and BLE bonding information.

#Storage Feature

RMK's storage system is enabled by the storage feature, which is part of the default feature set. Enabling BLE automatically pulls in storage, since BLE bonding data must be persisted to non-volatile storage. The host configurator protocols (rynk and vial) rely on storage to persist keymap edits across reboots but do not enable it themselves, so keep it enabled when you use them.

#Storage Configuration

By default, RMK saves data to your microcontroller's internal flash memory.

• For users configuring with keyboard.toml, the default storage space details are located in the rmk-config/src/default_config folder. If your microcontroller's configuration isn't found there, RMK uses the last num_sectors flash sectors of your microcontroller's internal flash memory. num_sectors defaults to 8 when a [dfu] section is present, either in your keyboard.toml or in the chip default (nRF52840, nice!nano, RP2040 and Pico W ship one), otherwise 2. On nRF BLE builds without DFU, the default start address 0 means 0x60000 instead of the end of flash. See Storage configuration for all [storage] fields.

• For Rust API users, create a StorageConfig struct and pass it to initialize_keymap_and_storage, which sets up the storage from your flash peripheral. Besides start_addr and num_sectors, StorageConfig carries clear_storage and clear_layout, which erase everything or only the layout at boot:

use rmk::config::{BehaviorConfig, PositionalConfig, StorageConfig};
use rmk::{KeymapData, initialize_keymap_and_storage};

let storage_config = StorageConfig::default();
let mut behavior_config = BehaviorConfig::default();
let per_key_config = PositionalConfig::default();
let mut keymap_data = KeymapData::new(keymap::get_default_keymap());
let (keymap, mut storage) = initialize_keymap_and_storage(
    &mut keymap_data,
    flash,
    &storage_config,
    &mut behavior_config,
    &per_key_config,
)
.await;

// `storage` is a runnable — pass it to `run_all!` with everything else
run_all!(matrix, storage, usb_transport, keyboard).await;

#When stored data is erased

On boot, RMK might erase the stored data according to the change of the current firmware:

Editing the keymap in keyboard.toml or in Rust does not by itself replace what is stored: the stored keymap wins on boot, so edits made over Vial or Rynk survive a reflash. To hand the win back to the firmware, set clear_layout = true in the [storage] section of keyboard.toml (or the same field of StorageConfig), flash once, then set it back to false. It rewrites the keymap, encoders, behaviors, combos, forks, morses and macros from the firmware and keeps the BLE pairings; clear_storage = true erases everything, pairings included.