SD-card firmware update + X3 bootloader compatibility (#1786)

src/network/OtaBootSwitch.h

@@ -0,0 +1,43 @@
+#pragma once
+
+#include <esp_partition.h>
+
+#include <cstddef>
+#include <cstdint>
+
+// X4 (and X3) factory bootloaders accept our patch_firmware_image.py-patched
+// firmware.bin (web flasher proves this), but the running ESP-IDF's
+// esp_image_verify rejects with bogus efuse-blk-rev errors. Both SD-card and
+// OTA update paths bypass that runtime check by writing the OTA app partition
+// raw and updating otadata directly — same scheme as the web flasher
+// (crosspoint-reader-docs/src/lib/flasher/OtaPartition.ts).
+//
+// Layout reference: esp_flash_partitions.h. CRC covers ota_seq (4 bytes) only.
+
+namespace ota_boot {
+
+struct __attribute__((packed)) SelectEntry {
+  uint32_t ota_seq;
+  uint8_t seq_label[20];
+  uint32_t ota_state;
+  uint32_t crc;
+};
+static_assert(sizeof(SelectEntry) == 32, "SelectEntry must be 32 bytes");
+
+constexpr uint32_t kOtaImgNew = 0;      // ESP_OTA_IMG_NEW
+constexpr uint32_t kOtaImgInvalid = 3;  // ESP_OTA_IMG_INVALID
+constexpr uint32_t kOtaImgAborted = 4;  // ESP_OTA_IMG_ABORTED
+constexpr size_t kOtaSeqCrcLen = 4;
+
+// CRC32-LE over the 4-byte ota_seq, init UINT32_MAX. Matches IDF and web flasher.
+uint32_t computeSeqCrc(uint32_t seq);
+
+// Switch the bootloader's selected app partition to `dest` by writing a fresh
+// otadata entry into the inactive otadata slot. Bypasses esp_ota_set_boot_partition's
+// esp_image_verify call. The bytes in `dest` must already be a valid app image
+// (e.g. patch_firmware_image.py output) — caller is responsible for that.
+//
+// Returns true on success.
+bool switchTo(const esp_partition_t* dest);
+
+}  // namespace ota_boot