diff --git a/sys/xtimer/Kconfig b/sys/xtimer/Kconfig
index b4de1eb6e5..ea4c879a0d 100644
--- a/sys/xtimer/Kconfig
+++ b/sys/xtimer/Kconfig
@@ -20,7 +20,6 @@ if MODULE_XTIMER
 
 config MODULE_XTIMER_NO_ZTIMER_DEFAULT
     bool "xtimer does not select ztimer"
-    default y
 
 config MODULE_AUTO_INIT_XTIMER
     bool "Auto-init xtimer"
diff --git a/sys/xtimer/Makefile.dep b/sys/xtimer/Makefile.dep
index 4d141a49aa..ae685c3ced 100644
--- a/sys/xtimer/Makefile.dep
+++ b/sys/xtimer/Makefile.dep
@@ -7,7 +7,6 @@ DEFAULT_MODULE += auto_init_xtimer
 # dependency inclusion order issues
 FEATURES_REQUIRED += periph_timer
 
-USEMODULE += xtimer_no_ztimer_default
 ifeq (,$(filter xtimer_no_ztimer_default,$(USEMODULE)))
   ifeq (,$(filter xtimer_on_ztimer,$(USEMODULE)))
     USEMODULE += ztimer_xtimer_compat
diff --git a/tests/bench_sys_base64/Makefile.ci b/tests/bench_sys_base64/Makefile.ci
index 7b28dc1447..69c36480c6 100644
--- a/tests/bench_sys_base64/Makefile.ci
+++ b/tests/bench_sys_base64/Makefile.ci
@@ -4,4 +4,5 @@ BOARD_INSUFFICIENT_MEMORY := \
     arduino-uno \
     atmega328p \
     atmega328p-xplained-mini \
+    nucleo-l011k4 \
     #
diff --git a/tests/cpp11_condition_variable/Makefile.ci b/tests/cpp11_condition_variable/Makefile.ci
index e2bfd595ea..466326bb96 100644
--- a/tests/cpp11_condition_variable/Makefile.ci
+++ b/tests/cpp11_condition_variable/Makefile.ci
@@ -2,4 +2,5 @@ BOARD_INSUFFICIENT_MEMORY := \
     nucleo-l011k4 \
     samd10-xmini \
     stm32f030f4-demo \
+    stk3200 \
     #
diff --git a/tests/driver_cst816s/Makefile.ci b/tests/driver_cst816s/Makefile.ci
new file mode 100644
index 0000000000..dac7727874
--- /dev/null
+++ b/tests/driver_cst816s/Makefile.ci
@@ -0,0 +1,4 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    nucleo-l011k4 \
+    stm32f030f4-demo \
+    #
diff --git a/tests/driver_ds1307/Makefile.ci b/tests/driver_ds1307/Makefile.ci
index 7b28dc1447..69c36480c6 100644
--- a/tests/driver_ds1307/Makefile.ci
+++ b/tests/driver_ds1307/Makefile.ci
@@ -4,4 +4,5 @@ BOARD_INSUFFICIENT_MEMORY := \
     arduino-uno \
     atmega328p \
     atmega328p-xplained-mini \
+    nucleo-l011k4 \
     #
diff --git a/tests/driver_lpd8808/Makefile.ci b/tests/driver_lpd8808/Makefile.ci
index 518b330a9e..dac7727874 100644
--- a/tests/driver_lpd8808/Makefile.ci
+++ b/tests/driver_lpd8808/Makefile.ci
@@ -1,3 +1,4 @@
 BOARD_INSUFFICIENT_MEMORY := \
+    nucleo-l011k4 \
     stm32f030f4-demo \
     #
diff --git a/tests/driver_ph_oem/Makefile.ci b/tests/driver_ph_oem/Makefile.ci
new file mode 100644
index 0000000000..dac7727874
--- /dev/null
+++ b/tests/driver_ph_oem/Makefile.ci
@@ -0,0 +1,4 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    nucleo-l011k4 \
+    stm32f030f4-demo \
+    #
diff --git a/tests/driver_scd30/Makefile.ci b/tests/driver_scd30/Makefile.ci
index 558ab2153a..c79c55eff9 100644
--- a/tests/driver_scd30/Makefile.ci
+++ b/tests/driver_scd30/Makefile.ci
@@ -1,3 +1,5 @@
 BOARD_INSUFFICIENT_MEMORY := \
+    nucleo-l011k4 \
+    samd10-xmini \
     stk3200 \
     #
diff --git a/tests/evtimer_mbox/Makefile.ci b/tests/evtimer_mbox/Makefile.ci
new file mode 100644
index 0000000000..b9ff275375
--- /dev/null
+++ b/tests/evtimer_mbox/Makefile.ci
@@ -0,0 +1,3 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    nucleo-l011k4 \
+    #
diff --git a/tests/pkg_wolfssl/Makefile.ci b/tests/pkg_wolfssl/Makefile.ci
index c45f6d7bab..e50e0cd47b 100644
--- a/tests/pkg_wolfssl/Makefile.ci
+++ b/tests/pkg_wolfssl/Makefile.ci
@@ -18,6 +18,7 @@ BOARD_INSUFFICIENT_MEMORY := \
     slstk3400a \
     spark-core \
     stk3200 \
+    spark-core \
     stm32f030f4-demo \
     stm32f0discovery \
     stm32g0316-disco \
diff --git a/tests/sys_sema_inv/Makefile.ci b/tests/sys_sema_inv/Makefile.ci
index 69c36480c6..29b1d9aae2 100644
--- a/tests/sys_sema_inv/Makefile.ci
+++ b/tests/sys_sema_inv/Makefile.ci
@@ -4,5 +4,6 @@ BOARD_INSUFFICIENT_MEMORY := \
     arduino-uno \
     atmega328p \
     atmega328p-xplained-mini \
+    nucleo-f031k6 \
     nucleo-l011k4 \
     #
diff --git a/tests/trickle/Makefile.ci b/tests/trickle/Makefile.ci
new file mode 100644
index 0000000000..b9ff275375
--- /dev/null
+++ b/tests/trickle/Makefile.ci
@@ -0,0 +1,3 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    nucleo-l011k4 \
+    #