v0.5.9: El Torito boot detection + retroactive re-introspect; static SSO login button

Storage / boot detection
- Add El Torito boot-catalog detection to ISO introspection. This is the
  authoritative "can this boot at all?" signal: any ISO with a boot catalog
  (BSDs, ESXi, firmware tools, custom spins) is bootable via iPXE sanboot;
  a data/appliance ISO (e.g. a VMware vCenter bundle) has none and is
  honestly flagged. Replaces the crude ">1.5 GB ⇒ unbootable" size guess.
- Re-introspect stale LOCAL ISOs on startup via an introspection-revision
  gate (INTROSPECT_REV). ISOs uploaded by an older binary carried a frozen
  family/boot profile — most visibly a Windows 11 ISO tagged Unknown before
  the UDF/UTF-16 detection landed, which then showed "won't boot" forever.
  An upgrade now re-probes and fixes them in place; no delete-and-re-upload.
- WebUI bootability() keys off family / kernel / el_torito / remote-source
  instead of the size heuristic; dashboard family counts now bucket
  Windows / Linux / other honestly instead of lumping everything non-Windows
  under "Linux".

SSO login button
- The "Sign in with …" button keyed off the auth-gated /api/sso, which 401s
  pre-auth — so the button only survived on a stale in-memory config and
  vanished instance-wide on any fresh login-page load. Ship a minimal,
  non-sensitive SSO descriptor (enabled + idp_name + idp_logo_url, no
  metadata/entity-ID) on the public /api/me; the login card reads that.
  The button is now static whenever SSO is usable.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

.gitignore

@@ -11,3 +11,6 @@ data/work/
 .claude/settings.local.json
 .claude/worktrees/
 .claude/scheduled_tasks.lock
+
+# local editor / agent settings (not part of the project)
+.claude/

Cargo.lock

@@ -2669,7 +2669,7 @@ checksum = "c08d65885ee38876c4f86fa503fb49d7b507c2b62552df7c70b2fce627e06381"
 
 [[package]]
 name = "openpxe"
-version = "0.5.8"
+version = "0.5.9"
 dependencies = [
  "anyhow",
  "axum",
@@ -2691,7 +2691,7 @@ dependencies = [
 
 [[package]]
 name = "openpxe-core"
-version = "0.5.8"
+version = "0.5.9"
 dependencies = [
  "anyhow",
  "base64",
@@ -2718,7 +2718,7 @@ dependencies = [
 
 [[package]]
 name = "openpxe-dhcp-proxy"
-version = "0.5.8"
+version = "0.5.9"
 dependencies = [
  "anyhow",
  "bytes",
@@ -2732,7 +2732,7 @@ dependencies = [
 
 [[package]]
 name = "openpxe-http-api"
-version = "0.5.8"
+version = "0.5.9"
 dependencies = [
  "anyhow",
  "axum",
@@ -2768,7 +2768,7 @@ dependencies = [
 
 [[package]]
 name = "openpxe-ipxe-assets"
-version = "0.5.8"
+version = "0.5.9"
 dependencies = [
  "openpxe-core",
  "rust-embed",
@@ -2778,7 +2778,7 @@ dependencies = [
 
 [[package]]
 name = "openpxe-iso-store"
-version = "0.5.8"
+version = "0.5.9"
 dependencies = [
  "anyhow",
  "bcrypt",
@@ -2807,7 +2807,7 @@ dependencies = [
 
 [[package]]
 name = "openpxe-tftp"
-version = "0.5.8"
+version = "0.5.9"
 dependencies = [
  "anyhow",
  "bytes",
@@ -2821,7 +2821,7 @@ dependencies = [
 
 [[package]]
 name = "openpxe-webui"
-version = "0.5.8"
+version = "0.5.9"
 
 [[package]]
 name = "p256"

Cargo.toml

@@ -12,7 +12,7 @@ members = [
 ]
 
 [workspace.package]
-version = "0.5.8"
+version = "0.5.9"
 edition = "2021"
 rust-version = "1.95"
 license = "MIT OR Apache-2.0"

README.md

@@ -14,7 +14,7 @@
 </p>
 
 <p align="center">
-  <img alt="release"   src="https://img.shields.io/badge/release-v0.5.5-2874d7" />
+  <img alt="release"   src="https://img.shields.io/badge/release-v0.5.8-2874d7" />
   <img alt="license"   src="https://img.shields.io/badge/license-MIT%20%7C%20Apache--2.0-59824f" />
   <img alt="rust"      src="https://img.shields.io/badge/built%20with-Rust-fb8841?logo=rust&logoColor=white" />
   <img alt="container" src="https://img.shields.io/badge/container--native-OCI%20%C2%B7%20OpenShift-2496ED?logo=docker&logoColor=white" />

crates/core/src/lib.rs

@@ -36,4 +36,4 @@ pub use profile::DeployProfile;
 pub use queue::{DeploymentQueue, QueueEntry};
 pub use saml::{IdpMetadata, SamlError, SpParams, VerifiedPrincipal, VerifiedResponse};
 pub use settings::{Settings, SettingsStore, TimeoutAction};
-pub use sso::{SsoConfig, SsoStore};
+pub use sso::{SsoConfig, SsoLoginInfo, SsoStore};

crates/core/src/sso.rs

@@ -73,6 +73,23 @@ impl SsoConfig {
     }
 }
 
+/// The minimal, non-sensitive slice of the SSO config that the **pre-auth**
+/// login screen needs to render the "Sign in with …" button. Carries only
+/// the display affordances — never the metadata XML/URL or entity ID, which
+/// stay behind the auth-gated `/api/sso`. Served as part of the public
+/// `/api/me` so the button renders reliably whether or not anyone is signed
+/// in (v0.5.9: fixes the button vanishing because `/api/sso` 401s pre-auth).
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
+pub struct SsoLoginInfo {
+    /// True only when SSO is *usable* (enabled AND a metadata source is
+    /// present) — i.e. clicking the button will actually reach an IdP.
+    pub enabled: bool,
+    /// Button label, e.g. "STC AD". Empty falls back to "SSO" in the UI.
+    pub idp_name: String,
+    /// Optional IdP logo rendered on the button. Empty = no image.
+    pub idp_logo_url: String,
+}
+
 /// In-memory + on-disk SSO settings registry.
 #[derive(Debug, Clone)]
 pub struct SsoStore {
@@ -111,6 +128,19 @@ impl SsoStore {
         self.inner.read().clone()
     }
 
+    /// Public, non-sensitive descriptor for the login screen. Safe to
+    /// expose pre-auth — it's exactly what the "Sign in with …" button
+    /// keys off, with no metadata/entity-ID leakage. v0.5.9.
+    #[must_use]
+    pub fn login_info(&self) -> SsoLoginInfo {
+        let cfg = self.inner.read();
+        SsoLoginInfo {
+            enabled: cfg.is_usable(),
+            idp_name: cfg.idp_name.clone(),
+            idp_logo_url: cfg.idp_logo_url.clone(),
+        }
+    }
+
     /// Replace the whole config in one shot. Light validation: metadata
     /// XML and URL are length-capped so an operator can't OOM us by
     /// pasting a 10 GiB blob; the IdP UI tab clamps the input visually,

crates/http-api/src/auth.rs

@@ -319,6 +319,12 @@ pub async fn api_me(State(state): State<AppState>, headers: axum::http::HeaderMa
     // and the logo asset is public, so this leaks nothing sensitive.
     let has_custom_logo = state.branding.has_any_web_logo();
     let logo_rev = state.branding.logo_rev();
+    // v0.5.9: ship the non-sensitive SSO descriptor with every /api/me so
+    // the pre-auth login screen can render the "Sign in with …" button
+    // reliably. Previously the button keyed off the auth-gated /api/sso,
+    // which 401s when logged out — the button only survived on a stale
+    // in-memory config and vanished on any fresh login-page load.
+    let sso = state.sso.login_info();
     if !state.admin.is_configured() {
         return (
             StatusCode::OK,
@@ -327,6 +333,7 @@ pub async fn api_me(State(state): State<AppState>, headers: axum::http::HeaderMa
                 "authenticated": false,
                 "has_custom_logo": has_custom_logo,
                 "logo_rev": logo_rev,
+                "sso": sso,
             })),
         )
             .into_response();
@@ -343,6 +350,7 @@ pub async fn api_me(State(state): State<AppState>, headers: axum::http::HeaderMa
                 "session_user": u,
                 "has_custom_logo": has_custom_logo,
                 "logo_rev": logo_rev,
+                "sso": sso,
             })),
         )
             .into_response(),
@@ -353,6 +361,7 @@ pub async fn api_me(State(state): State<AppState>, headers: axum::http::HeaderMa
                 "authenticated": false,
                 "has_custom_logo": has_custom_logo,
                 "logo_rev": logo_rev,
+                "sso": sso,
             })),
         )
             .into_response(),

crates/iso-store/src/introspect.rs

@@ -13,7 +13,7 @@ use serde::{Deserialize, Serialize};
 use std::io::{Read, Seek, SeekFrom};
 use std::path::Path;
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize, Default)]
 #[serde(rename_all = "snake_case")]
 pub enum DistroFamily {
     DebianUbuntu,
@@ -22,10 +22,22 @@ pub enum DistroFamily {
     Arch,
     Alpine,
     WindowsPe,
+    #[default]
     Unknown,
 }
 
-#[derive(Debug, Clone, Serialize, Deserialize)]
+/// Bumped whenever the introspection logic changes in a way that should
+/// re-classify already-uploaded ISOs. On startup the store re-runs
+/// `introspect` on any *local* ISO whose persisted report predates this
+/// revision (see `IsoStore::load_from_disk`), so an upgrade fixes stale
+/// metadata — e.g. a Windows 11 ISO tagged `Unknown` by an older binary —
+/// without the operator having to delete and re-upload it.
+///
+/// rev 1 (v0.5.9): added El Torito boot-catalog detection + broadened
+/// Windows (UDF/UTF-16) detection becomes retroactive.
+pub const INTROSPECT_REV: u32 = 1;
+
+#[derive(Debug, Clone, Default, Serialize, Deserialize)]
 pub struct IntrospectionReport {
     pub family: DistroFamily,
     pub volume_label: Option<String>,
@@ -35,17 +47,28 @@ pub struct IntrospectionReport {
     pub initrd_paths: Vec<String>,
     /// True if `sources/boot.wim` present — Windows install media.
     pub has_boot_wim: bool,
+    /// True if the ISO carries an El Torito boot catalog — i.e. it is
+    /// bootable by BIOS/UEFI firmware and therefore by iPXE `sanboot`
+    /// (emulated CD). This is the authoritative "can this boot at all?"
+    /// signal for ISOs we can't classify as Linux or Windows (BSDs, ESXi,
+    /// firmware tools, custom spins). A *data* ISO (e.g. a VMware vCenter
+    /// appliance bundle) has no boot catalog and reports `false`. v0.5.9.
+    #[serde(default)]
+    pub el_torito: bool,
+    /// Revision of the introspection logic that produced this report. Old
+    /// `meta.json` files without the field deserialize as 0, which is
+    /// below [`INTROSPECT_REV`], triggering a one-time re-introspect on
+    /// the next startup. v0.5.9.
+    #[serde(default)]
+    pub introspect_rev: u32,
 }
 
 /// Probe an ISO file on disk. Never fails — on unrecoverable IO error we log
 /// and return an `Unknown` family so the uploader still sees a record.
 pub fn introspect(path: &Path) -> IntrospectionReport {
     let mut report = IntrospectionReport {
-        family: DistroFamily::Unknown,
-        volume_label: None,
-        kernel_path: None,
-        initrd_paths: Vec::new(),
-        has_boot_wim: false,
+        introspect_rev: INTROSPECT_REV,
+        ..Default::default()
     };
 
     let Ok(mut f) = std::fs::File::open(path) else {
@@ -68,6 +91,11 @@ pub fn introspect(path: &Path) -> IntrospectionReport {
         }
     }
 
+    // Does the ISO have an El Torito boot catalog? This is what decides
+    // whether an ISO we *can't* otherwise classify is bootable at all —
+    // a bootable ISO sanboots; a data/appliance ISO (no catalog) can't.
+    report.el_torito = detect_el_torito(&mut f);
+
     // Cheap content scan: read the first ~64 MiB, look for signature filenames.
     // This is enough to identify `sources/boot.wim` (Windows) and common
     // kernel/initrd paths for the major Linux distros.
@@ -222,6 +250,44 @@ fn filename_looks_windows(path: &Path) -> bool {
     TOKENS.iter().any(|t| name.contains(t))
 }
 
+/// The boot-system identifier string in an El Torito Boot Record Volume
+/// Descriptor (offset 7, NUL-padded to 32 bytes).
+const EL_TORITO_ID: &[u8] = b"EL TORITO SPECIFICATION";
+
+/// Detect an El Torito boot catalog — the marker that an ISO is bootable
+/// by BIOS/UEFI firmware (and thus by iPXE `sanboot`).
+///
+/// The ISO9660 Volume Descriptor Set starts at LBA 16 (offset 0x8000) and
+/// runs one 2048-byte descriptor per sector until a Set Terminator
+/// (type 0xFF). A Boot Record descriptor (type 0x00) whose 32-byte boot
+/// system identifier reads "EL TORITO SPECIFICATION" means the image
+/// declares an El Torito boot catalog. We only confirm its presence — we
+/// don't parse the catalog (sanboot/the firmware does that). The walk is
+/// capped so a malformed/huge image can't spin us. v0.5.9.
+fn detect_el_torito(f: &mut std::fs::File) -> bool {
+    let mut vd = [0u8; 2048];
+    for lba in 16u64..32 {
+        if f.seek(SeekFrom::Start(lba * 2048)).is_err() || f.read_exact(&mut vd).is_err() {
+            return false;
+        }
+        // Every descriptor in the set carries the "CD001" magic; once it's
+        // missing we've walked off the end of a valid set.
+        if &vd[1..6] != b"CD001" {
+            return false;
+        }
+        match vd[0] {
+            // Boot Record descriptor carrying the El Torito signature.
+            0x00 if vd[7..7 + EL_TORITO_ID.len()] == *EL_TORITO_ID => return true,
+            // Volume Descriptor Set Terminator — nothing bootable found.
+            0xFF => return false,
+            // Any other descriptor (incl. a non-El-Torito boot record) —
+            // keep walking the set.
+            _ => {}
+        }
+    }
+    false
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -260,6 +326,40 @@ mod tests {
         assert!(!contains_utf16le_ci(b"boot.wim plain ascii", "boot.wim"));
     }
 
+    #[test]
+    fn el_torito_boot_catalog_detected() {
+        let dir = tempfile::tempdir().unwrap();
+        // Helper: stamp a 2048-byte descriptor at `lba` with type + magic.
+        let stamp = |img: &mut [u8], lba: usize, ty: u8| {
+            let off = lba * 2048;
+            img[off] = ty;
+            img[off + 1..off + 6].copy_from_slice(b"CD001");
+        };
+
+        // Bootable image: PVD @16, El Torito Boot Record @17, terminator @18.
+        let mut boot = vec![0u8; 2048 * 19];
+        stamp(&mut boot, 16, 0x01);
+        stamp(&mut boot, 17, 0x00);
+        boot[17 * 2048 + 7..17 * 2048 + 7 + EL_TORITO_ID.len()].copy_from_slice(EL_TORITO_ID);
+        stamp(&mut boot, 18, 0xFF);
+        let bp = dir.path().join("boot.iso");
+        std::fs::write(&bp, &boot).unwrap();
+        let mut f = std::fs::File::open(&bp).unwrap();
+        assert!(
+            detect_el_torito(&mut f),
+            "El Torito boot record should match"
+        );
+
+        // Data/appliance image: PVD @16, terminator @17, no boot record.
+        let mut data = vec![0u8; 2048 * 18];
+        stamp(&mut data, 16, 0x01);
+        stamp(&mut data, 17, 0xFF);
+        let dp = dir.path().join("data.iso");
+        std::fs::write(&dp, &data).unwrap();
+        let mut f2 = std::fs::File::open(&dp).unwrap();
+        assert!(!detect_el_torito(&mut f2), "data ISO has no boot catalog");
+    }
+
     #[test]
     fn filename_hint_catches_windows_isos() {
         use std::path::Path;

crates/iso-store/src/nfs_share.rs

@@ -57,7 +57,7 @@
 //! UI to ask for. (If a future server needs Kerberos or non-default
 //! uid mapping we can add those, but for ISO read access nobody does.)
 
-use crate::introspect::{DistroFamily, IntrospectionReport};
+use crate::introspect::IntrospectionReport;
 use crate::store::{generate_boot_entries_for, slugify_str, IsoSource, IsoStore};
 use bytes::Bytes;
 use nfs3_client::tokio::TokioConnector;
@@ -399,13 +399,7 @@ impl NfsShareManager {
             // Same approach as SMB: no real introspection over the
             // network in v0.4.67. The boot-entry generator falls back
             // to filename-based sanboot detection.
-            let report = IntrospectionReport {
-                family: DistroFamily::Unknown,
-                volume_label: None,
-                kernel_path: None,
-                initrd_paths: Vec::new(),
-                has_boot_wim: false,
-            };
+            let report = IntrospectionReport::default();
             let boot_entries = generate_boot_entries_for(&iso_id, &entry.filename, &report);
             let source = IsoSource::Nfs {
                 share_id: share.id.clone(),

crates/iso-store/src/sftp_share.rs

@@ -56,7 +56,7 @@
 //! hint}` error shape is shared so the storage tab renders all three
 //! protocols through one code path.
 
-use crate::introspect::{DistroFamily, IntrospectionReport};
+use crate::introspect::IntrospectionReport;
 use crate::store::{generate_boot_entries_for, slugify_str, IsoSource, IsoStore};
 use bytes::Bytes;
 use openpxe_core::{Error, Result};
@@ -480,13 +480,7 @@ impl SftpShareManager {
             // register `Unknown` and let the boot-entry generator fall
             // back to filename-based detection. SFTP *could* do bounded
             // PVD reads (it has random access) — a follow-up can add it.
-            let report = IntrospectionReport {
-                family: DistroFamily::Unknown,
-                volume_label: None,
-                kernel_path: None,
-                initrd_paths: Vec::new(),
-                has_boot_wim: false,
-            };
+            let report = IntrospectionReport::default();
             let boot_entries = generate_boot_entries_for(&iso_id, &entry.filename, &report);
             let source = IsoSource::Sftp {
                 share_id: share.id.clone(),

crates/iso-store/src/smb_share.rs

@@ -56,7 +56,7 @@
 //! streaming. A follow-up release can add libsmbclient-based seek if
 //! a real workload needs it.
 
-use crate::introspect::{DistroFamily, IntrospectionReport};
+use crate::introspect::IntrospectionReport;
 use crate::store::{generate_boot_entries_for, slugify_str, IsoSource, IsoStore};
 use openpxe_core::{Error, Result};
 use parking_lot::Mutex;
@@ -470,13 +470,7 @@ impl SmbShareManager {
             // and the operator gets *something* bootable. A follow-up
             // release can do a bounded `smbclient get` of the first
             // 64 KiB for real detection.
-            let report = IntrospectionReport {
-                family: DistroFamily::Unknown,
-                volume_label: None,
-                kernel_path: None,
-                initrd_paths: Vec::new(),
-                has_boot_wim: false,
-            };
+            let report = IntrospectionReport::default();
             let boot_entries = generate_boot_entries_for(&iso_id, &entry.filename, &report);
             let source = IsoSource::Smb {
                 share_id: share.id.clone(),

crates/iso-store/src/store.rs

@@ -223,7 +223,8 @@ impl IsoStore {
                 continue;
             }
             if let Ok(text) = tokio::fs::read_to_string(&p).await {
-                if let Ok(meta) = serde_json::from_str::<IsoMeta>(&text) {
+                if let Ok(mut meta) = serde_json::from_str::<IsoMeta>(&text) {
+                    self.reintrospect_if_stale(&mut meta).await;
                     self.insert(meta);
                 }
             }
@@ -231,6 +232,46 @@ impl IsoStore {
         Ok(())
     }
 
+    /// v0.5.9: re-run introspection on a *local* ISO whose persisted report
+    /// predates the current logic. ISOs uploaded by an older binary carry a
+    /// stale family/boot profile — most visibly a Windows 11 ISO tagged
+    /// `Unknown` before the UDF/El-Torito detection landed, which then shows
+    /// as "won't boot" forever. Re-probing on startup fixes them in place,
+    /// no delete-and-re-upload. Bounded: only `Local` sources (we have the
+    /// bytes locally) below [`introspect::INTROSPECT_REV`], so it runs at
+    /// most once per ISO per upgrade. The probe reads up to ~64 MiB, so we
+    /// push it onto the blocking pool to keep the async runtime responsive.
+    async fn reintrospect_if_stale(&self, meta: &mut IsoMeta) {
+        if !matches!(meta.source, IsoSource::Local)
+            || meta.introspection.introspect_rev >= crate::introspect::INTROSPECT_REV
+        {
+            return;
+        }
+        let path = self.iso_path(&meta.id);
+        if !path.exists() {
+            return;
+        }
+        let Ok(fresh) = tokio::task::spawn_blocking(move || introspect(&path)).await else {
+            tracing::warn!(target: "openpxe::iso", id = %meta.id, "re-introspect task failed");
+            return;
+        };
+        let before = meta.introspection.family;
+        meta.introspection = fresh;
+        meta.boot_entries = generate_boot_entries(&meta.id, &meta.filename, &meta.introspection);
+        if let Err(e) = self.persist_meta(meta).await {
+            tracing::warn!(target: "openpxe::iso", id = %meta.id, "re-introspect persist: {e}");
+            return;
+        }
+        tracing::info!(
+            target: "openpxe::iso",
+            id = %meta.id,
+            from = ?before,
+            to = ?meta.introspection.family,
+            el_torito = meta.introspection.el_torito,
+            "re-introspected stale ISO metadata"
+        );
+    }
+
     fn insert(&self, meta: IsoMeta) {
         self.inner.write().isos.insert(meta.id.clone(), meta);
     }
@@ -687,13 +728,7 @@ mod tests {
             size_bytes: 0,
             sha256_hex: None,
             uploaded_at: OffsetDateTime::now_utc(),
-            introspection: IntrospectionReport {
-                family: DistroFamily::Unknown,
-                volume_label: None,
-                kernel_path: None,
-                initrd_paths: vec![],
-                has_boot_wim: false,
-            },
+            introspection: IntrospectionReport::default(),
             boot_entries: vec![],
             source: IsoSource::Local,
             password_hash: None,

crates/webui/src/app.js

@@ -165,17 +165,30 @@
     if (fam === 'windows_pe') {
       return { ok: true };
     }
-    if (!iso.introspection.kernel_path) {
-      // Not Windows and no Linux kernel/initrd detected. Small images can
-      // still try the sanboot fallback; large ones almost certainly aren't
-      // network-bootable installers (e.g. appliance bundles like VMware
-      // VCSA) — flag them clearly instead of with a Linux-centric message.
-      if (iso.size_bytes > 1.5 * 1024 * 1024 * 1024) {
-        return { ok: false, reason: "not a recognized network-bootable installer (no Windows or Linux boot files found) — this image can't be PXE-booted" };
-      }
-      return { ok: true, warn: 'no kernel detected — sanboot fallback may not work' };
+    // Linux with a detected kernel/initrd — direct kernel+initrd boot.
+    if (iso.introspection.kernel_path) {
+      return { ok: true };
     }
-    return { ok: true };
+    // v0.5.9: any other ISO that carries an El Torito boot catalog is
+    // bootable via iPXE sanboot (emulated CD) — BSDs, ESXi, firmware
+    // tools, custom Linux spins. This replaces the old "> 1.5 GB ⇒
+    // unbootable" size guess with the authoritative on-disk boot signal,
+    // so a large bootable ISO is no longer mislabeled and a Windows ISO
+    // re-introspected on upgrade lights up correctly.
+    if (iso.introspection.el_torito) {
+      return { ok: true, warn: 'generic bootable ISO — boots via sanboot (emulated CD)' };
+    }
+    // Remote-share ISOs aren't introspected (no random access over the
+    // network), so el_torito is unknown — assume bootable and let sanboot
+    // try rather than cry wolf.
+    const remote = iso.source && iso.source.kind && iso.source.kind !== 'local';
+    if (remote) {
+      return { ok: true, warn: 'remote ISO — not introspected; sanboot is attempted at boot' };
+    }
+    // Local ISO with no Windows/Linux boot files and no El Torito catalog:
+    // a data/appliance image (e.g. a VMware vCenter bundle), not a bootable
+    // installer.
+    return { ok: false, reason: 'data/appliance ISO — no El Torito boot catalog and no Windows/Linux installer files, so it can’t be PXE-booted' };
   }
 
   // v0.5.2: pretty label for an unattended file's detected kind.
@@ -291,14 +304,23 @@
         el('div', {class: 'card'}, el('div', {class: 'stat'}, [
           el('div', {class: 'label'}, 'Images available'),
           el('div', {class: 'value'}, String(isos.length)),
-          el('div', {class: 'trend'},
-            isos.filter(i => i.introspection.family === 'windows_pe').length + ' Windows · ' +
-            isos.filter(i => i.introspection.family !== 'windows_pe').length + ' Linux  ·  ' +
+          el('div', {class: 'trend'}, (() => {
+            // v0.5.9: count families honestly. Anything that isn't a known
+            // Linux family or Windows lands in "other" (data/appliance ISOs
+            // like VMware VCSA, or as-yet-unclassified images) instead of
+            // being lumped under "Linux".
+            const LINUX = ['debian_ubuntu', 'rhel_fedora', 'opensuse', 'arch', 'alpine'];
+            const win = isos.filter(i => i.introspection.family === 'windows_pe').length;
+            const lin = isos.filter(i => LINUX.includes(i.introspection.family)).length;
+            const other = isos.length - win - lin;
             // v0.4.67+v0.5.5: count all remote-share protocols. Label
             // generically since operators may use any mix of SMB/NFS/SFTP.
-            ((status.smb_share_reachable || 0) + (status.nfs_share_reachable || 0) + (status.sftp_share_reachable || 0)) +
-            ' remote share' +
-            (((status.smb_share_reachable || 0) + (status.nfs_share_reachable || 0) + (status.sftp_share_reachable || 0)) === 1 ? '' : 's')),
+            const remote = (status.smb_share_reachable || 0) + (status.nfs_share_reachable || 0) + (status.sftp_share_reachable || 0);
+            const parts = [win + ' Windows', lin + ' Linux'];
+            if (other > 0) parts.push(other + ' other');
+            parts.push(remote + ' remote share' + (remote === 1 ? '' : 's'));
+            return parts.join('  ·  ');
+          })()),
         ])),
         el('div', {class: 'card'}, el('div', {class: 'stat'}, [
           el('div', {class: 'label'}, 'Uptime'),
@@ -2280,7 +2302,9 @@
     // own self-contained <form>; when SSO is enabled, a distinct
     // "Sign in with …" button sits below a divider — the credential
     // fields no longer double as the SSO trigger.
-    const ssoLive = ssoConfig && ssoConfig.enabled && (ssoConfig.metadata_url || ssoConfig.metadata);
+    // `enabled` from /api/me already means "usable" (enabled AND a metadata
+    // source is configured), so the button only shows when SSO will work.
+    const ssoLive = !!(ssoConfig && ssoConfig.enabled);
     const ssoBlock = ssoLive
       ? el('div', {class:'sso-block'}, [
           el('div', {class:'auth-divider'}, el('span', {}, 'or')),
@@ -2525,10 +2549,12 @@
         ])));
       return;
     }
-    // Preload the SSO config so the login card can offer the operator
-    // an "Sign in with X" button when configured. Failure is harmless.
-    try { ssoConfig = await fetch('/api/sso').then(r => r.ok ? r.json() : null); }
-    catch { ssoConfig = null; }
+    // v0.5.9: the login card's "Sign in with …" button keys off the SSO
+    // descriptor that /api/me now carries (public, non-sensitive: enabled
+    // + idp_name + idp_logo_url). It's available signed in or out, so the
+    // button is static — it no longer relied on the auth-gated /api/sso,
+    // which 401s pre-auth and made the button vanish on fresh login loads.
+    ssoConfig = me.sso || null;
 
     if (me.setup_required) {
       showAuthScreen('setup');