From 11c101c2350515ddf1da2e01bb29e6bc86785b38 Mon Sep 17 00:00:00 2001
From: Ian Gulliver <github@flamingcow.io>
Date: Sun, 12 Apr 2026 22:22:54 +0900
Subject: [PATCH] Flash status: scan PICOBIN blocks for per-slot validity and
 version

---
 cmd/picomap/main.go       |  7 ++++++-
 firmware/include/wire.h   | 15 ++++++++++++---
 firmware/lib/handlers.cpp | 40 ++++++++++++++++++++++++++++++++++-----
 lib/client/types.go       | 10 +++++++++-
 4 files changed, 62 insertions(+), 10 deletions(-)

diff --git a/cmd/picomap/main.go b/cmd/picomap/main.go
index f95bc25..1cde157 100644
--- a/cmd/picomap/main.go
+++ b/cmd/picomap/main.go
@@ -227,7 +227,12 @@ func cmdFlashStatus(args []string) error {
 		slog.Info("flash-status",
 			"via", t.name,
 			"boot_partition", status.BootPartition,
-			"boot_type", status.BootType)
+			"slot_a_valid", status.SlotA.Valid,
+			"slot_a_version", status.SlotA.Version,
+			"slot_a_hash_ok", status.SlotA.HashOK,
+			"slot_b_valid", status.SlotB.Valid,
+			"slot_b_version", status.SlotB.Version,
+			"slot_b_hash_ok", status.SlotB.HashOK)
 	}
 	return nil
 }
diff --git a/firmware/include/wire.h b/firmware/include/wire.h
index c1969f5..aebfa3d 100644
--- a/firmware/include/wire.h
+++ b/firmware/include/wire.h
@@ -128,12 +128,21 @@ struct RequestFlashStatus {
     auto as_tuple() { return std::tie(); }
 };
 
+struct SlotInfo {
+    bool valid;
+    uint32_t version;
+    bool hash_ok;
+    auto as_tuple() const { return std::tie(valid, version, hash_ok); }
+    auto as_tuple() { return std::tie(valid, version, hash_ok); }
+};
+
 struct ResponseFlashStatus {
     static constexpr int8_t ext_id = 15;
     int8_t boot_partition;
-    uint8_t boot_type;
-    auto as_tuple() const { return std::tie(boot_partition, boot_type); }
-    auto as_tuple() { return std::tie(boot_partition, boot_type); }
+    SlotInfo slot_a;
+    SlotInfo slot_b;
+    auto as_tuple() const { return std::tie(boot_partition, slot_a, slot_b); }
+    auto as_tuple() { return std::tie(boot_partition, slot_a, slot_b); }
 };
 
 struct RequestListTests {
diff --git a/firmware/lib/handlers.cpp b/firmware/lib/handlers.cpp
index dbec25d..29e242f 100644
--- a/firmware/lib/handlers.cpp
+++ b/firmware/lib/handlers.cpp
@@ -3,12 +3,15 @@
 #include "pico/bootrom.h"
 #include "hardware/flash.h"
 #include "hardware/watchdog.h"
+#include "boot/picobin.h"
 #include "dispatch.h"
 #include "net.h"
 #include "debug_log.h"
 
 static constexpr uint32_t XIP_BASE_ADDR = 0x10000000;
 static constexpr uint32_t FLASH_SIZE = 2 * 1024 * 1024;
+static constexpr uint32_t SLOT_A_OFFSET = 0x00000;
+static constexpr uint32_t SLOT_B_OFFSET = 0x80000;
 static boot_reason detected_boot_reason;
 
 static void poke_watchdog() {
@@ -88,16 +91,43 @@ std::optional<ResponseFlashWrite> handle_flash_write(const responder&, const Req
     return ResponseFlashWrite{};
 }
 
+static SlotInfo scan_slot(uint32_t flash_offset) {
+    SlotInfo info{};
+    constexpr uint32_t scan_limit = 4096;
+    auto* scan = reinterpret_cast<const uint32_t*>(XIP_BASE_ADDR + flash_offset);
+    auto* scan_end = scan + scan_limit / 4;
+    while (scan < scan_end && *scan != PICOBIN_BLOCK_MARKER_START) scan++;
+    if (scan >= scan_end) return info;
+    info.valid = true;
+
+    auto* p = reinterpret_cast<const uint8_t*>(scan + 1);
+    auto* end = reinterpret_cast<const uint8_t*>(scan + 64);
+    while (p + 2 <= end) {
+        uint8_t type = p[0];
+        uint8_t size_words = p[1];
+        if (type == PICOBIN_BLOCK_ITEM_2BS_LAST) break;
+        uint32_t item_bytes = static_cast<uint32_t>(size_words) * 4;
+        if (p + item_bytes > end) break;
+        if (type == PICOBIN_BLOCK_ITEM_1BS_VERSION && size_words >= 2) {
+            auto* words = reinterpret_cast<const uint16_t*>(p + 4);
+            uint16_t minor = words[0];
+            uint16_t major = words[1];
+            info.version = (static_cast<uint32_t>(major) << 16) | minor;
+        }
+        p += item_bytes;
+    }
+    return info;
+}
+
 std::optional<ResponseFlashStatus> handle_flash_status(const responder&, const RequestFlashStatus&) {
     ResponseFlashStatus resp;
     boot_info_t bi;
-    if (rom_get_boot_info(&bi)) {
+    if (rom_get_boot_info(&bi))
         resp.boot_partition = bi.partition;
-        resp.boot_type = bi.boot_type;
-    } else {
+    else
         resp.boot_partition = -1;
-        resp.boot_type = 0;
-    }
+    resp.slot_a = scan_slot(SLOT_A_OFFSET);
+    resp.slot_b = scan_slot(SLOT_B_OFFSET);
     return resp;
 }
 
diff --git a/lib/client/types.go b/lib/client/types.go
index c7ccdcf..0bdc69c 100644
--- a/lib/client/types.go
+++ b/lib/client/types.go
@@ -63,9 +63,17 @@ type RequestReboot struct{}
 type ResponseReboot struct{}
 
 type RequestFlashStatus struct{}
+
+type SlotInfo struct {
+	Valid   bool
+	Version uint32
+	HashOK  bool
+}
+
 type ResponseFlashStatus struct {
 	BootPartition int8
-	BootType      uint8
+	SlotA         SlotInfo
+	SlotB         SlotInfo
 }
 
 type RequestListTests struct{}