Support flashing to partitions other than factory

.gitignore

@@ -1,2 +1,4 @@
 /target
+/Cargo.lock
 *.swp
+/.vscode

espflash/src/error.rs

@@ -314,7 +314,7 @@ pub enum PartitionTableError {
     InvalidSubType(#[from] InvalidSubTypeError),
     #[error(transparent)]
     #[diagnostic(transparent)]
-    NoFactoryApp(#[from] NoFactoryAppError),
+    NoApp(#[from] NoAppError),
     #[error(transparent)]
     #[diagnostic(transparent)]
     UnalignedPartitionError(#[from] UnalignedPartitionError),
@@ -469,19 +469,19 @@ impl InvalidSubTypeError {
 }
 
 #[derive(Debug, Error, Diagnostic)]
-#[error("No factory app partition was found")]
+#[error("No app partition was found")]
 #[diagnostic(
-    code(espflash::partition_table::no_factory_app),
-    help("Partition table must contain a factory app partition")
+    code(espflash::partition_table::no_app),
+    help("Partition table must contain a factory or ota app partition")
 )]
-pub struct NoFactoryAppError {
+pub struct NoAppError {
     #[source_code]
     source_code: String,
 }
 
-impl NoFactoryAppError {
+impl NoAppError {
     pub fn new(source: &str) -> Self {
-        NoFactoryAppError {
+        NoAppError {
             source_code: source.into(),
         }
     }

espflash/src/image_format/esp32bootloader.rs

@@ -12,6 +12,7 @@ use crate::{
     error::{Error, FlashDetectError},
     flasher::FlashSize,
     image_format::{EspCommonHeader, ImageFormat, SegmentHeader, ESP_MAGIC, WP_PIN_DISABLED},
+    partition_table::Type,
     Chip, PartitionTable,
 };
 
@@ -123,8 +124,12 @@ impl<'a> Esp32BootloaderFormat<'a> {
 
         // The default partition table contains the "factory" partition, and if a user
         // provides a partition table via command-line then the validation step confirms
-        // this is present, so it's safe to unwrap.
-        let factory_partition = partition_table.find("factory").unwrap();
+        // that at least one "app" partition is present. We prefer the "factory" partition,
+        // and use any available "app" partitions if not present.
+        let factory_partition = partition_table
+            .find("factory")
+            .or_else(|| partition_table.find_by_type(Type::App))
+            .unwrap();
 
         let flash_segment = RomSegment {
             addr: factory_partition.offset(),

espflash/src/partition_table.rs

@@ -10,7 +10,7 @@ use regex::Regex;
 use serde::{Deserialize, Deserializer, Serialize};
 
 use crate::error::{
-    CSVError, DuplicatePartitionsError, InvalidSubTypeError, NoFactoryAppError,
+    CSVError, DuplicatePartitionsError, InvalidSubTypeError, NoAppError,
     OverlappingPartitionsError, PartitionTableError, UnalignedPartitionError,
 };
 
@@ -264,6 +264,10 @@ impl PartitionTable {
         self.partitions.iter().find(|&p| p.name == name)
     }
 
+    pub fn find_by_type(&self, ty: Type) -> Option<&Partition> {
+        self.partitions.iter().find(|&p| p.ty == ty)
+    }
+
     fn validate(&self, source: &str) -> Result<(), PartitionTableError> {
         for partition in &self.partitions {
             if let Some(line) = &partition.line {
@@ -318,10 +322,8 @@ impl PartitionTable {
             }
         }
 
-        if self.find("factory").is_none() {
-            return Err(PartitionTableError::NoFactoryApp(NoFactoryAppError::new(
-                source,
-            )));
+        if self.find_by_type(Type::App).is_none() {
+            return Err(PartitionTableError::NoApp(NoAppError::new(source)));
         }
 
         Ok(())
@@ -590,6 +592,24 @@ phy_init, data, phy,     0xf000,  0x1000,
 factory,  app,  factory, 0x10000,  1M,
 a,        data,  spiffs, 0x110000, 1M,
 b,        data,  spiffs, 0x210000, 1M,
+";
+
+    const PTABLE_NO_FACTORY: &str = "
+# ESP-IDF Partition Table
+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x4000,
+otadata,  data, ota,     0xd000,  0x2000,
+phy_init, data, phy,     0xf000,  0x1000,
+ota_0,    app,  ota_0,   , 1M,
+ota_1,    app,  ota_1,   , 1M,
+";
+
+    const PTABLE_NO_APP: &str = "
+# ESP-IDF Partition Table
+# Name,   Type, SubType, Offset,  Size, Flags
+nvs,      data, nvs,     0x9000,  0x4000,
+otadata,  data, ota,     0xd000,  0x2000,
+phy_init, data, phy,     0xf000,  0x1000,
 ";
 
     #[test]
@@ -629,6 +649,11 @@ b,        data,  spiffs, 0x210000, 1M,
 
         let pt_spiffs = PartitionTable::try_from_str(PTABLE_SPIFFS);
         assert!(pt_spiffs.is_ok());
+
+        PartitionTable::try_from_str(PTABLE_NO_FACTORY)
+            .expect("Failed to parse partition table without factory partition");
+        PartitionTable::try_from_str(PTABLE_NO_APP)
+            .expect_err("Failed to reject partition table without factory or ota partition");
     }
 
     #[test]