diff --git a/misc/build.func b/misc/build.func
index 4ed0f5850..e64fb896c 100644
--- a/misc/build.func
+++ b/misc/build.func
@@ -4391,12 +4391,16 @@ EOF'
     echo ""
     echo -en "${YW}Select option [1-${max_option}] (default: 1, auto-remove in 60s): ${CL}"
 
-    # Ensure terminal is sane before reading input (lxc-attach|tee may corrupt tty state)
+    # Restore terminal state after lxc-attach|tee pipeline
     stty sane 2>/dev/null || true
+    # Drain stale input from terminal buffer (lxc-attach|tee leaves residual data
+    # that causes read to return immediately with empty input)
+    dd iflag=nonblock if=/dev/tty of=/dev/null 2>/dev/null || true
+    sleep 0.3
 
-    # Read directly from /dev/tty (fresh open = clean state, no inherited corruption)
+    # Read user choice
     local response=""
-    if read -t 60 -r response </dev/tty 2>/dev/null; then
+    if read -t 60 -r response </dev/tty; then
       case "${response:-1}" in
       1)
         # Remove container
diff --git a/misc/error_handler.func b/misc/error_handler.func
index 6f2b637a1..183aa2be8 100644
--- a/misc/error_handler.func
+++ b/misc/error_handler.func
@@ -286,10 +286,12 @@ error_handler() {
         echo -en "${YW}Remove broken container ${CTID}? (Y/n) [auto-remove in 60s]: ${CL}"
       fi
 
-      # Reset terminal state and read directly from /dev/tty (fresh open = clean state)
+      # Reset terminal state and flush stale input from buffer
       stty sane 2>/dev/null || true
+      dd iflag=nonblock if=/dev/tty of=/dev/null 2>/dev/null || true
+      sleep 0.3
       local response=""
-      if read -t 60 -r response </dev/tty 2>/dev/null; then
+      if read -t 60 -r response </dev/tty; then
         if [[ -z "$response" || "$response" =~ ^[Yy]$ ]]; then
           echo ""
           if declare -f msg_info >/dev/null 2>&1; then
diff --git a/misc/tools.func b/misc/tools.func
index 0ebde4bd5..e9d08dc51 100644
--- a/misc/tools.func
+++ b/misc/tools.func
@@ -934,7 +934,11 @@ upgrade_package() {
 # ------------------------------------------------------------------------------
 # Repository availability check with caching
 # ------------------------------------------------------------------------------
-declare -A _REPO_CACHE 2>/dev/null || true
+# Note: Must use -gA (global) because tools.func is sourced inside update_os()
+# function scope. Plain 'declare -A' would create a local variable that gets
+# destroyed when update_os() returns, causing "unbound variable" errors later
+# when setup_postgresql/verify_repo_available tries to access the cache key.
+declare -gA _REPO_CACHE 2>/dev/null || declare -A _REPO_CACHE 2>/dev/null || true
 
 verify_repo_available() {
   local repo_url="$1"