diff --git a/.github/workflows/container-validation.yml b/.github/workflows/container-validation.yml
index 96e8eae..5205276 100644
--- a/.github/workflows/container-validation.yml
+++ b/.github/workflows/container-validation.yml
@@ -110,6 +110,9 @@ jobs:
       - name: simplerisk-minimal credential escaping
         run: ./simplerisk-minimal/test_escaping.sh
 
+      - name: simplerisk-minimal DB TLS flags per mysql client
+        run: ./simplerisk-minimal/test_db_ssl_flags.sh
+
       - name: simplerisk-minimal Apache worker setting
         run: ./simplerisk-minimal/test_set_apache_workers.sh
 
diff --git a/simplerisk-minimal/README.md b/simplerisk-minimal/README.md
index acf584f..237c303 100644
--- a/simplerisk-minimal/README.md
+++ b/simplerisk-minimal/README.md
@@ -65,7 +65,7 @@ docker run -d --name simplerisk -e SIMPLERISK_DB_PASSWORD=pass -e SIMPLERISK_DB_
 | `DB_SETUP_PASS` | `root` (the bundled `stack.yml` ships `simplerisk_setup`) | Used when `DB_SETUP=automatic\|automatic-only\|delete`. Password of the privileged MySQL user used **only** to install the SimpleRisk schema and create the app DB user. In `stack.yml` it is also the bundled MySQL root password; since that MySQL is not exposed outside the stack network, a documented default is used for the zero-config trial. Override it (and `MYSQL_ROOT_PASSWORD` in `stack.yml`) for any non-trial deployment. |
 | `DB_SETUP_WAIT` | 20 | Used when `DB_SETUP=automatic\|automatic-only`. Time, in seconds, the application is going to wait to set up the database. Useful if you are deploying the database and SimpleRisk at the same time |
 | `DB_UPGRADE` | `null` (Accepts any value) | Run SimpleRisk's release-by-release database **schema upgrade** against an already-installed database (as opposed to `DB_SETUP`, which installs a fresh one), then continue running (`automatic`) or stop the container (`automatic-only`, for a one-shot upgrade job). Uses the `SIMPLERISK_DB_*` application credentials — no privileged user. The structured per-release JSON result is written to the container log, and the container exits non-zero if the upgrade fails. Idempotent — a no-op when the schema is already current |
-| `DB_SSL_ENABLED` | `false` (off) | Opt-in, used when `DB_SETUP=automatic\|automatic-only\|delete`. Set to exactly `true` to require TLS on the privileged setup/delete MySQL client connection (adds `--ssl-mode=REQUIRED --enable-cleartext-plugin`). Any other value, or unset, leaves the connection unchanged (plaintext-capable) |
+| `DB_SSL_ENABLED` | `false` (off) | Opt-in, used when `DB_SETUP=automatic\|automatic-only\|delete`. Set to exactly `true` to require TLS on the privileged setup/delete MySQL client connection (adds `--ssl-mode=REQUIRED --enable-cleartext-plugin`; on the arm64 image, whose `mysql` is MariaDB's client and has no `--ssl-mode`, it adds the equivalent `--ssl --skip-ssl-verify-server-cert`). Any other value, or unset, leaves the connection unchanged (plaintext-capable) |
 | `SIMPLERISK_DB_HOSTNAME` | `localhost` | Hostname of the database server |
 | `SIMPLERISK_DB_PORT` | 3306 | Port to contact the database |
 | `SIMPLERISK_DB_USERNAME` |`simplerisk` | User name to be used to access the SimpleRisk database |
diff --git a/simplerisk-minimal/common/entrypoint.sh b/simplerisk-minimal/common/entrypoint.sh
index 89e5d9e..6ef2d7c 100644
--- a/simplerisk-minimal/common/entrypoint.sh
+++ b/simplerisk-minimal/common/entrypoint.sh
@@ -69,7 +69,7 @@ config_define() {
 # password via MYSQL_PWD, so no value is subject to shell interpretation.
 mysql_setup() {
 	local -a flags=()
-	# DB_SSL_FLAGS is an internal constant ("--ssl-mode=... --enable-cleartext-plugin")
+	# DB_SSL_FLAGS is an internal value from set_db_ssl_flags (client-specific TLS flags)
 	[ -n "${DB_SSL_FLAGS:-}" ] && read -ra flags <<< "$DB_SSL_FLAGS"
 	MYSQL_PWD="$DB_SETUP_PASS" mysql ${flags[@]+"${flags[@]}"} \
 		-u "$DB_SETUP_USER" -h "$SIMPLERISK_DB_HOSTNAME" -P "$SIMPLERISK_DB_PORT"
@@ -473,6 +473,17 @@ set_mail_settings(){
 	[ -n "${MAIL_PASSWORD:-}" ] && apply_mail_setting phpmailer_password "$MAIL_PASSWORD" || true
 }
 
+# True when the mysql client understands --ssl-mode. Oracle's client does (amd64 image). MariaDB's
+# does not, and it is the only client packaged for arm64 (MySQL's apt repo has no arm64 builds), so
+# there `mysql` rejects it with "unknown variable 'ssl-mode=REQUIRED'". If the client cannot be asked,
+# assume Oracle's, which is what these flags were written for.
+mysql_client_supports_ssl_mode() {
+	local help
+	help=$(mysql --help 2>/dev/null) || return 0
+	[ -n "$help" ] || return 0
+	grep -q -- '--ssl-mode' <<< "$help"
+}
+
 set_db_ssl_flags(){
 	# Some databases require the privileged setup/delete mysql client to send
 	# its credential via the cleartext auth plugin, which the server only
@@ -480,7 +491,14 @@ set_db_ssl_flags(){
 	# rather than a static password). Set DB_SSL_ENABLED=true to opt in.
 	DB_SSL_FLAGS=""
 	if [ "${DB_SSL_ENABLED:-}" = "true" ]; then
-		DB_SSL_FLAGS="--ssl-mode=REQUIRED --enable-cleartext-plugin"
+		if mysql_client_supports_ssl_mode; then
+			DB_SSL_FLAGS="--ssl-mode=REQUIRED --enable-cleartext-plugin"
+		else
+			# MariaDB client: --ssl makes TLS mandatory and --skip-ssl-verify-server-cert matches
+			# REQUIRED (encrypt, do not verify the certificate). The cleartext plugin is built in;
+			# --enable-cleartext-plugin is obsolete there and only prints a warning.
+			DB_SSL_FLAGS="--ssl --skip-ssl-verify-server-cert"
+		fi
 	fi
 }
 
diff --git a/simplerisk-minimal/test_db_ssl_flags.sh b/simplerisk-minimal/test_db_ssl_flags.sh
new file mode 100755
index 0000000..7a45c16
--- /dev/null
+++ b/simplerisk-minimal/test_db_ssl_flags.sh
@@ -0,0 +1,72 @@
+#!/usr/bin/env bash
+# Verifies set_db_ssl_flags in common/entrypoint.sh picks TLS flags the installed mysql client
+# understands. Oracle's client (amd64 image) takes --ssl-mode=REQUIRED --enable-cleartext-plugin.
+# MariaDB's client (arm64 image: Debian's default-mysql-client, since MySQL's apt repo has no arm64
+# packages) rejects --ssl-mode ("unknown variable 'ssl-mode=REQUIRED'"), which made every DB setup
+# and delete fail on Graviton against a TLS-only RDS. Its equivalent is --ssl plus
+# --skip-ssl-verify-server-cert (TLS required, server certificate not verified: the same as
+# REQUIRED); the cleartext plugin is built in and --enable-cleartext-plugin is obsolete there.
+#
+# `mysql` is faked with --help output shaped like the real clients (the MariaDB lines were captured
+# from mariadb 11.8.6 in the arm64 image). Requires bash >= 4.
+set -uo pipefail
+cd "$(dirname "$(readlink -f "$0")")" || exit 1
+
+fail=0
+ok()  { echo "ok: $1"; }
+bad() { echo "FAIL: $1"; echo "  expected: $2"; echo "  actual:   $3"; fail=1; }
+check() { [ "$2" = "$3" ] && ok "$1" || bad "$1" "$2" "$3"; }
+
+work=$(mktemp -d); trap 'rm -rf "$work"' EXIT
+mkdir -p "$work/mysql-oracle" "$work/mariadb" "$work/none"
+
+cat > "$work/mysql-oracle/mysql" <<'FAKE'
+#!/bin/sh
+cat <<'HELP'
+mysql  Ver 8.4.8 for Linux on x86_64 (MySQL Community Server - GPL)
+  --ssl-mode=name     SSL connection mode.
+  --ssl-ca=name       CA file in PEM format.
+  --enable-cleartext-plugin
+                      Enable/disable the clear text authentication plugin.
+HELP
+FAKE
+cat > "$work/mariadb/mysql" <<'FAKE'
+#!/bin/sh
+cat <<'HELP'
+mysql from 11.8.6-MariaDB, client 15.2 for debian-linux-gnu (aarch64)
+  --ssl               Enable SSL for connection (automatically enabled with
+  --ssl-ca=name       CA file in PEM format (check OpenSSL docs, implies
+  --ssl-verify-server-cert
+                      Verify server's "Common Name" in its cert against
+HELP
+FAKE
+chmod +x "$work/mysql-oracle/mysql" "$work/mariadb/mysql"
+
+# Pull in only the functions under test.
+eval "$(sed -n '/^mysql_client_supports_ssl_mode() {/,/^}/p;/^set_db_ssl_flags(){/,/^}/p' common/entrypoint.sh)"
+
+# flags_with <client dir|none> <DB_SSL_ENABLED value|unset>
+flags_with() {
+  ( PATH="$work/$1:/usr/bin:/bin"
+    [ "$1" = none ] && PATH="$work/none:/nonexistent"
+    if [ "$2" = unset ]; then unset DB_SSL_ENABLED; else DB_SSL_ENABLED="$2"; fi
+    set_db_ssl_flags; printf '%s' "$DB_SSL_FLAGS" )
+}
+
+# Oracle client: behaviour must be exactly what it was (amd64 images depend on it).
+check "oracle client + DB_SSL_ENABLED=true" "--ssl-mode=REQUIRED --enable-cleartext-plugin" "$(flags_with mysql-oracle true)"
+# MariaDB client: no flag it rejects.
+got=$(flags_with mariadb true)
+check "mariadb client + DB_SSL_ENABLED=true" "--ssl --skip-ssl-verify-server-cert" "$got"
+case "$got" in *--ssl-mode*) bad "mariadb flags must not contain --ssl-mode" "(none)" "$got";; *) ok "mariadb flags contain no --ssl-mode";; esac
+case "$got" in *--enable-cleartext-plugin*) bad "mariadb flags must not contain the obsolete --enable-cleartext-plugin" "(none)" "$got";; *) ok "mariadb flags contain no --enable-cleartext-plugin";; esac
+# Opt-in only: anything but exactly "true" leaves the connection unchanged, for either client.
+for c in mysql-oracle mariadb; do
+  for v in unset false TRUE 1 ""; do
+    check "$c + DB_SSL_ENABLED='$v' -> no flags" "" "$(flags_with $c "$v")"
+  done
+done
+# If the client cannot be asked (not on PATH), keep the historical flags rather than guess.
+check "no mysql on PATH + DB_SSL_ENABLED=true keeps the historical flags" "--ssl-mode=REQUIRED --enable-cleartext-plugin" "$(flags_with none true)"
+
+exit $fail