Migrate serialization from Bincode to Postcard

- Replaced Bincode with Postcard for serialization/deserialization across configs and save operations.
- Simplified struct derives by removing `bincode`-specific traits.
- Updated `Cargo.toml` and `Cargo.lock` to include `postcard` and dependencies.
- Added padding stripping for deserialization and improved error handling.
- Adjusted serialization logic in `savegame_manager.rs` and related modules.

Software/MainBoard/rust/Cargo.lock

@@ -83,7 +83,6 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "36eaf5d7b090263e8150820482d5d93cd964a81e4019913c972f4edcc6edb740"
 dependencies = [
  "bincode_derive",
- "serde",
  "unty",
 ]
 
@@ -225,6 +224,15 @@ dependencies = [
  "regex",
 ]
 
+[[package]]
+name = "cobs"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0fa961b519f0b462e3a3b4a34b64d119eeaca1d59af726fe450bbba07a9fc0a1"
+dependencies = [
+ "thiserror",
+]
+
 [[package]]
 name = "const-default"
 version = "1.0.0"
@@ -746,6 +754,12 @@ dependencies = [
  "embedded-hal 1.0.0",
 ]
 
+[[package]]
+name = "embedded-io"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ef1a6892d9eef45c8fa6b9e0086428a2cca8491aca8f787c534a3d6d0bcb3ced"
+
 [[package]]
 name = "embedded-io"
 version = "0.6.1"
@@ -1884,7 +1898,6 @@ name = "plant-ctrl2"
 version = "0.1.0"
 dependencies = [
  "async-trait",
- "bincode",
  "bytemuck",
  "canapi",
  "chrono",
@@ -1926,6 +1939,7 @@ dependencies = [
  "option-lock",
  "pca9535",
  "portable-atomic",
+ "postcard",
  "serde",
  "serde_json",
  "sntpc",
@@ -1971,6 +1985,18 @@ dependencies = [
  "syn 2.0.110",
 ]
 
+[[package]]
+name = "postcard"
+version = "1.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6764c3b5dd454e283a30e6dfe78e9b31096d9e32036b5d1eaac7a6119ccb9a24"
+dependencies = [
+ "cobs",
+ "embedded-io 0.4.0",
+ "embedded-io 0.6.1",
+ "serde",
+]
+
 [[package]]
 name = "powerfmt"
 version = "0.2.0"
@@ -2404,6 +2430,26 @@ dependencies = [
  "winapi-util",
 ]
 
+[[package]]
+name = "thiserror"
+version = "2.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4288b5bcbc7920c07a1149a35cf9590a2aa808e0bc1eafaade0b80947865fbc4"
+dependencies = [
+ "thiserror-impl",
+]
+
+[[package]]
+name = "thiserror-impl"
+version = "2.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ebc4ee7f67670e9b64d05fa4253e753e016c6c95ff35b89b7941d6b856dec1d5"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.110",
+]
+
 [[package]]
 name = "thread_local"
 version = "1.1.9"

Software/MainBoard/rust/Cargo.toml

@@ -91,7 +91,7 @@ embedded-savegame = { version = "0.3.0" }
 # Serialization / codecs
 serde = { version = "1.0.228", features = ["derive", "alloc"], default-features = false }
 serde_json = { version = "1.0.145", default-features = false, features = ["alloc"] }
-bincode = { version = "2.0.1", default-features = false, features = ["derive", "alloc"] }
+postcard = { version = "1.1.3", default-features = false, features = ["alloc"] }
 
 # Time and time zones
 chrono = { version = "0.4.42", default-features = false, features = ["iana-time-zone", "alloc", "serde"] }

Software/MainBoard/rust/src/config.rs

@@ -1,10 +1,9 @@
 use crate::hal::PLANT_COUNT;
 use crate::plant_state::PlantWateringMode;
 use alloc::string::{String, ToString};
-use bincode::{Decode, Encode};
 use serde::{Deserialize, Serialize};
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
 #[serde(default)]
 pub struct NetworkConfig {
     pub ap_ssid: String,
@@ -31,7 +30,7 @@ impl Default for NetworkConfig {
     }
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
 #[serde(default)]
 pub struct NightLampConfig {
     pub enabled: bool,
@@ -54,7 +53,7 @@ impl Default for NightLampConfig {
     }
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
 #[serde(default)]
 pub struct TankConfig {
     pub tank_sensor_enabled: bool,
@@ -79,20 +78,20 @@ impl Default for TankConfig {
     }
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default)]
 pub enum BatteryBoardVersion {
     #[default]
     Disabled,
     WchI2cSlave,
 }
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default)]
 pub enum BoardVersion {
     Initial,
     #[default]
     V4,
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default)]
 pub struct BoardHardware {
     pub board: BoardVersion,
     pub battery: BatteryBoardVersion,
@@ -100,7 +99,7 @@ pub struct BoardHardware {
     pub pump_corrosion_protection: bool,
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Default)]
 #[serde(default)]
 pub struct PlantControllerConfig {
     pub hardware: BoardHardware,
@@ -111,7 +110,7 @@ pub struct PlantControllerConfig {
     pub timezone: Option<String>,
 }
 
-#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq)]
 #[serde(default)]
 pub struct PlantConfig {
     pub mode: PlantWateringMode,

Software/MainBoard/rust/src/fat_error.rs

@@ -230,16 +230,8 @@ impl<E: fmt::Debug> From<ExpanderError<I2cDeviceError<E>>> for FatError {
     }
 }
 
-impl From<bincode::error::DecodeError> for FatError {
-    fn from(value: bincode::error::DecodeError) -> Self {
-        FatError::Eeprom24x {
-            error: format!("{value:?}"),
-        }
-    }
-}
-
-impl From<bincode::error::EncodeError> for FatError {
-    fn from(value: bincode::error::EncodeError) -> Self {
+impl From<postcard::Error> for FatError {
+    fn from(value: postcard::Error) -> Self {
         FatError::Eeprom24x {
             error: format!("{value:?}"),
         }

Software/MainBoard/rust/src/hal/esp.rs

@@ -582,7 +582,15 @@ impl Esp<'_> {
     /// Retries once on flash error.
     pub(crate) async fn save_config(&mut self, config: Vec<u8>) -> FatResult<()> {
         let timestamp = self.get_time().to_rfc3339();
-        self.savegame.save(config.as_slice(), &timestamp)
+        self.savegame.save(config.as_slice(), &timestamp)?;
+
+        match self.savegame.load_latest()? {
+            None => bail!("Config save verification failed: no latest save found"),
+            Some(data) => {
+                let _: PlantControllerConfig = serde_json::from_slice(&data)?;
+                Ok(())
+            }
+        }
     }
 
     /// Delete a specific save slot by erasing it on flash.

Software/MainBoard/rust/src/hal/mod.rs

@@ -51,7 +51,6 @@ use alloc::boxed::Box;
 use alloc::format;
 use alloc::sync::Arc;
 use async_trait::async_trait;
-use bincode::{Decode, Encode};
 use canapi::SensorSlot;
 use chrono::{DateTime, FixedOffset, Utc};
 use core::cell::RefCell;
@@ -118,7 +117,7 @@ pub static I2C_DRIVER: OnceLock<
     embassy_sync::blocking_mutex::Mutex<CriticalSectionRawMutex, RefCell<I2c<Blocking>>>,
 > = OnceLock::new();
 
-#[derive(Debug, PartialEq, Clone, Copy, Encode, Decode)]
+#[derive(Debug, PartialEq, Clone, Copy, Serialize, Deserialize)]
 pub enum Sensor {
     A,
     B,

Software/MainBoard/rust/src/hal/rtc.rs

@@ -1,7 +1,6 @@
 use crate::fat_error::FatResult;
 use crate::hal::Box;
 use async_trait::async_trait;
-use bincode::{Decode, Encode};
 use chrono::{DateTime, Utc};
 use ds323x::ic::DS3231;
 use ds323x::interface::I2cInterface;
@@ -29,7 +28,7 @@ pub trait RTCModuleInteraction {
     fn read(&mut self, offset: u32, data: &mut [u8]) -> FatResult<()>;
 }
 
-#[derive(Serialize, Deserialize, PartialEq, Debug, Default, Encode, Decode)]
+#[derive(Serialize, Deserialize, PartialEq, Debug, Default)]
 pub struct BackupHeader {
     pub timestamp: i64,
     pub(crate) crc16: u16,

Software/MainBoard/rust/src/hal/savegame_manager.rs

@@ -1,3 +1,4 @@
+use alloc::string::ToString;
 use alloc::vec::Vec;
 use embedded_savegame::storage::{Flash, Storage};
 use embedded_storage::nor_flash::{NorFlash, ReadNorFlash};
@@ -32,6 +33,19 @@ struct ParsedSave<'a> {
     data: &'a [u8],
 }
 
+fn strip_padding(data: &[u8]) -> &[u8] {
+    let mut end = data.len();
+    while end > 0 {
+        let b = data[end - 1];
+        if b == 0x00 || b == 0xFF {
+            end -= 1;
+        } else {
+            break;
+        }
+    }
+    &data[..end]
+}
+
 fn parse_save(data: &[u8]) -> FatResult<ParsedSave<'_>> {
     if data.len() < SAVE_HEADER_LEN {
         return Err(FatError::String {
@@ -60,7 +74,7 @@ fn parse_save(data: &[u8]) -> FatResult<ParsedSave<'_>> {
 
     Ok(ParsedSave {
         created_at,
-        data: &data[timestamp_end..],
+        data: strip_padding(&data[timestamp_end..]),
     })
 }
 
@@ -240,7 +254,7 @@ impl SavegameManager {
                         saves.push(SaveInfo {
                             idx,
                             len: 0,
-                            created_at: None,
+                            created_at: Some(err.to_string()),
                         });
                     }
                 }

Software/MainBoard/rust/src/hal/v4_hal.rs

@@ -12,7 +12,6 @@ use crate::log::{log, LogMessage};
 use alloc::boxed::Box;
 use alloc::string::ToString;
 use async_trait::async_trait;
-use bincode::config;
 use canapi::id::{classify, plant_id, MessageKind, IDENTIFY_CMD_OFFSET};
 use canapi::SensorSlot;
 use chrono::{DateTime, FixedOffset, Utc};
@@ -36,7 +35,6 @@ use measurements::{Current, Voltage};
 use pca9535::{GPIOBank, Pca9535Immediate, StandardExpanderInterface};
 
 pub const BACKUP_HEADER_MAX_SIZE: usize = 64;
-const CONFIG: config::Configuration = config::standard();
 
 const MPPT_CURRENT_SHUNT_OHMS: f64 = 0.05_f64;
 const TWAI_BAUDRATE: twai::BaudRate = twai::BaudRate::Custom(twai::TimingConfig {
@@ -543,7 +541,7 @@ impl<'a> BoardInteraction<'a> for V4<'a> {
     }
     async fn backup_config(&mut self, controller_config: &PlantControllerConfig) -> FatResult<()> {
         let mut buffer: [u8; 4096 - BACKUP_HEADER_MAX_SIZE] = [0; 4096 - BACKUP_HEADER_MAX_SIZE];
-        let length = bincode::encode_into_slice(controller_config, &mut buffer, CONFIG)?;
+        let length = postcard::to_slice(controller_config, &mut buffer)?.len();
         info!("Writing backup config of size {}", length);
         let mut checksum = X25.digest();
         checksum.update(&buffer[..length]);
@@ -556,7 +554,7 @@ impl<'a> BoardInteraction<'a> for V4<'a> {
             size: length as u16,
         };
         info!("Header is {:?}", header);
-        bincode::encode_into_slice(&header, &mut header_page_buffer, CONFIG)?;
+        postcard::to_slice(&header, &mut header_page_buffer)?;
         info!("Header is serialized");
         self.get_rtc_module().write(0, &header_page_buffer)?;
         info!("Header written");
@@ -600,7 +598,7 @@ impl<'a> BoardInteraction<'a> for V4<'a> {
             bail!("CRC mismatch in backup data")
         }
         info!("CRC is correct");
-        let (decoded, _) = bincode::decode_from_slice(&store[..], CONFIG)?;
+        let decoded = postcard::from_bytes(&store[..])?;
         info!("Backup data decoded");
         Ok(decoded)
     }
@@ -609,8 +607,7 @@ impl<'a> BoardInteraction<'a> for V4<'a> {
         let mut header_page_buffer = [0_u8; BACKUP_HEADER_MAX_SIZE];
         self.get_rtc_module().read(0, &mut header_page_buffer)?;
         info!("Read header page");
-        let info: Result<(BackupHeader, usize), bincode::error::DecodeError> =
-            bincode::decode_from_slice(&header_page_buffer[..], CONFIG);
+        let info = postcard::take_from_bytes::<BackupHeader>(&header_page_buffer[..]);
         info!("decoding header: {:?}", info);
         let (header, _) = info.context("Could not read backup header")?;
         Ok(header)

Software/MainBoard/rust/src/plant_state.rs

@@ -1,6 +1,5 @@
 use crate::hal::Moistures;
 use crate::{config::PlantConfig, hal::HAL, in_time_range};
-use bincode::{Decode, Encode};
 use chrono::{DateTime, TimeDelta, Utc};
 use chrono_tz::Tz;
 use serde::{Deserialize, Serialize};
@@ -73,7 +72,7 @@ impl PumpState {
     }
 }
 
-#[derive(Serialize, Deserialize, Clone, Copy, Debug, PartialEq, Encode, Decode)]
+#[derive(Serialize, Deserialize, Clone, Copy, Debug, PartialEq)]
 pub enum PlantWateringMode {
     Off,
     TargetMoisture,