Use MEPHI mirror, disable security repo, fix memtest in ISO build

- Switch all lb mirrors to mirror.mephi.ru/debian/ for faster/reliable downloads
- Disable security repo (--security false) — not needed for LiveCD
- Pin MEMTEST_VERSION=6.10-4 in VERSIONS, export to hook environment
- Set BEE_REQUIRE_MEMTEST=1 in build-in-container.sh — missing memtest is now fatal
- Fix 9100-memtest.hook.binary: add apt-get download fallback when lb
  binary_memtest has already purged the package cache; handle both 5.x
  (memtest86+x64.bin) and 6.x (memtest86+.bin) BIOS binary naming

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

iso/builder/VERSIONS

@@ -21,3 +21,4 @@ HIPBLASLT_VERSION=0.10.0.60304-76~22.04
 COMGR_VERSION=2.8.0.60304-76~22.04
 GO_VERSION=1.24.0
 AUDIT_VERSION=1.0.0
+MEMTEST_VERSION=6.10-4

iso/builder/auto/config

@@ -23,10 +23,10 @@ lb config noauto \
     --bootloaders "grub-efi,syslinux" \
     --debian-installer none \
     --archive-areas "main contrib non-free non-free-firmware" \
-    --mirror-bootstrap "https://deb.debian.org/debian" \
-    --mirror-chroot "https://deb.debian.org/debian" \
-    --mirror-binary "https://deb.debian.org/debian" \
-    --security true \
+    --mirror-bootstrap "http://mirror.mephi.ru/debian/" \
+    --mirror-chroot "http://mirror.mephi.ru/debian/" \
+    --mirror-binary "http://mirror.mephi.ru/debian/" \
+    --security false \
     --linux-flavours "amd64" \
     --linux-packages "${LB_LINUX_PACKAGES}" \
     --memtest memtest86+ \

iso/builder/build-in-container.sh

@@ -161,6 +161,7 @@ run_variant() {
             -e GOMODCACHE=/cache/go-mod \
             -e TMPDIR=/cache/tmp \
             -e BEE_CACHE_DIR=/cache/bee \
+            -e BEE_REQUIRE_MEMTEST=1 \
             -w /work \
             "${IMAGE_REF}" \
             sh /work/iso/builder/build.sh --variant "${_v}" \
@@ -175,6 +176,7 @@ run_variant() {
             -e GOMODCACHE=/cache/go-mod \
             -e TMPDIR=/cache/tmp \
             -e BEE_CACHE_DIR=/cache/bee \
+            -e BEE_REQUIRE_MEMTEST=1 \
             -w /work \
             "${IMAGE_REF}" \
             sh /work/iso/builder/build.sh --variant "${_v}"

iso/builder/build.sh

@@ -57,6 +57,7 @@ OVERLAY_STAGE_DIR="${DIST_DIR}/overlay-stage-${BUILD_VARIANT}"
 export BEE_GPU_VENDOR BEE_NVIDIA_MODULE_FLAVOR BUILD_VARIANT
 
 . "${BUILDER_DIR}/VERSIONS"
+export MEMTEST_VERSION
 export PATH="$PATH:/usr/local/go/bin"
 : "${BEE_REQUIRE_MEMTEST:=0}"
 

iso/builder/config/hooks/normal/9100-memtest.hook.binary

@@ -5,6 +5,8 @@ set -e
 
 : "${BEE_REQUIRE_MEMTEST:=0}"
 
+# memtest86+ 6.x uses memtest86+.bin (no x64 suffix) for the BIOS binary,
+# while 5.x used memtest86+x64.bin. We normalise both to x64 names in the ISO.
 MEMTEST_FILES="memtest86+x64.bin memtest86+x64.efi"
 BINARY_BOOT_DIR="binary/boot"
 GRUB_CFG="binary/boot/grub/grub.cfg"
@@ -26,13 +28,13 @@ fail_or_warn() {
 
 copy_memtest_file() {
     src="$1"
-    base="$(basename "$src")"
-    dst="${BINARY_BOOT_DIR}/${base}"
+    dst_name="${2:-$(basename "$src")}"
+    dst="${BINARY_BOOT_DIR}/${dst_name}"
 
     [ -f "$src" ] || return 1
     mkdir -p "${BINARY_BOOT_DIR}"
     cp "$src" "$dst"
-    log "copied ${base} from ${src}"
+    log "copied ${dst_name} from ${src}"
 }
 
 extract_memtest_from_deb() {
@@ -41,14 +43,42 @@ extract_memtest_from_deb() {
 
     log "extracting memtest payload from ${deb}"
     dpkg-deb -x "$deb" "$tmpdir"
-    for f in ${MEMTEST_FILES}; do
-        if [ -f "${tmpdir}/boot/${f}" ]; then
-            copy_memtest_file "${tmpdir}/boot/${f}"
-        fi
-    done
+
+    # EFI binary: both 5.x and 6.x use memtest86+x64.efi
+    if [ -f "${tmpdir}/boot/memtest86+x64.efi" ]; then
+        copy_memtest_file "${tmpdir}/boot/memtest86+x64.efi"
+    fi
+
+    # BIOS binary: 5.x = memtest86+x64.bin, 6.x = memtest86+.bin
+    if [ -f "${tmpdir}/boot/memtest86+x64.bin" ]; then
+        copy_memtest_file "${tmpdir}/boot/memtest86+x64.bin"
+    elif [ -f "${tmpdir}/boot/memtest86+.bin" ]; then
+        copy_memtest_file "${tmpdir}/boot/memtest86+.bin" "memtest86+x64.bin"
+    fi
+
     rm -rf "$tmpdir"
 }
 
+download_and_extract_memtest() {
+    tmpdl="$(mktemp -d)"
+    ver_arg=""
+    if [ -n "${MEMTEST_VERSION:-}" ]; then
+        ver_arg="=memtest86+=${MEMTEST_VERSION}"
+        log "downloading memtest86+=${MEMTEST_VERSION} from apt"
+    else
+        log "downloading memtest86+ from apt (no version pinned)"
+    fi
+    # shellcheck disable=SC2086
+    ( cd "$tmpdl" && apt-get download "memtest86+${ver_arg}" ) 2>/dev/null || true
+    deb="$(find "$tmpdl" -maxdepth 1 -type f -name 'memtest86+*.deb' 2>/dev/null | head -1)"
+    if [ -n "$deb" ]; then
+        extract_memtest_from_deb "$deb"
+    else
+        log "apt download of memtest86+ failed"
+    fi
+    rm -rf "$tmpdl"
+}
+
 ensure_memtest_binaries() {
     missing=0
     for f in ${MEMTEST_FILES}; do
@@ -56,10 +86,15 @@ ensure_memtest_binaries() {
     done
     [ "$missing" -eq 1 ] || return 0
 
+    # 1. Try files already placed by lb binary_memtest or chroot
     for root in chroot/boot /boot; do
         for f in ${MEMTEST_FILES}; do
             [ -f "${BINARY_BOOT_DIR}/${f}" ] || copy_memtest_file "${root}/${f}" || true
         done
+        # 6.x BIOS binary may lack x64 in name — copy with normalised name
+        if [ ! -f "${BINARY_BOOT_DIR}/memtest86+x64.bin" ]; then
+            copy_memtest_file "${root}/memtest86+.bin" "memtest86+x64.bin" || true
+        fi
     done
 
     missing=0
@@ -68,6 +103,7 @@ ensure_memtest_binaries() {
     done
     [ "$missing" -eq 1 ] || return 0
 
+    # 2. Try apt package cache (may be empty if lb binary_memtest already purged)
     for root in cache chroot/var/cache/apt/archives /var/cache/apt/archives; do
         [ -d "$root" ] || continue
         deb="$(find "$root" -type f \( -name 'memtest86+_*.deb' -o -name 'memtest86+*.deb' \) 2>/dev/null | head -1)"
@@ -76,6 +112,15 @@ ensure_memtest_binaries() {
         break
     done
 
+    missing=0
+    for f in ${MEMTEST_FILES}; do
+        [ -f "${BINARY_BOOT_DIR}/${f}" ] || missing=1
+    done
+    [ "$missing" -eq 1 ] || return 0
+
+    # 3. Fallback: download fresh from apt (lb binary_memtest purges the cache)
+    download_and_extract_memtest
+
     missing=0
     for f in ${MEMTEST_FILES}; do
         if [ ! -f "${BINARY_BOOT_DIR}/${f}" ]; then