diff --git a/misc/build.func b/misc/build.func
index e24d05d5..fcb77ca6 100644
--- a/misc/build.func
+++ b/misc/build.func
@@ -4601,7 +4601,9 @@ EOF'
     fi
 
     pct exec "$CTID" -- bash -c "apt-get update >/dev/null 2>&1 && apt-get install -y sudo curl mc gnupg2 jq >/dev/null 2>&1" || {
-      msg_warn "apt-get update failed, trying alternate mirrors..."
+      local failed_mirror
+      failed_mirror=$(pct exec "$CTID" -- bash -c "grep -m1 -oP '(?<=URIs: https?://)[^/]+' /etc/apt/sources.list.d/debian.sources 2>/dev/null || grep -m1 -oP '(?<=deb https?://)[^/]+' /etc/apt/sources.list 2>/dev/null" 2>/dev/null || echo "unknown")
+      msg_warn "apt-get update failed on ${failed_mirror}, trying alternate mirrors..."
       local mirror_exit=0
       pct exec "$CTID" -- bash -c '
         APT_BASE="sudo curl mc gnupg2 jq"
diff --git a/misc/install.func b/misc/install.func
index 99a27a6a..ddd177af 100644
--- a/misc/install.func
+++ b/misc/install.func
@@ -201,7 +201,9 @@ pkg_update() {
   case "$PKG_MANAGER" in
   apt)
     if ! $STD apt-get update; then
-      msg_warn "apt-get update failed, trying alternate mirrors..."
+      local failed_mirror
+      failed_mirror=$(grep -m1 -oP '(?<=URIs: https?://)[^/]+' /etc/apt/sources.list.d/debian.sources 2>/dev/null || grep -m1 -oP '(?<=deb https?://)[^/]+' /etc/apt/sources.list 2>/dev/null || echo "unknown")
+      msg_warn "apt-get update failed on ${failed_mirror}, trying alternate mirrors..."
       local eu_mirrors="ftp.de.debian.org ftp.fr.debian.org ftp.nl.debian.org ftp.uk.debian.org ftp.ch.debian.org ftp.se.debian.org ftp.it.debian.org ftp.fau.de ftp.halifax.rwth-aachen.de debian.mirror.lrz.de mirror.init7.net debian.ethz.ch mirrors.dotsrc.org debian.mirrors.ovh.net"
       local us_mirrors="ftp.us.debian.org ftp.ca.debian.org debian.csail.mit.edu mirrors.ocf.berkeley.edu mirrors.wikimedia.org debian.osuosl.org mirror.cogentco.com"
       local ap_mirrors="ftp.au.debian.org ftp.jp.debian.org ftp.tw.debian.org ftp.kr.debian.org ftp.hk.debian.org ftp.sg.debian.org mirror.aarnet.edu.au mirror.nitc.ac.in"