diff --git a/components/esp_system/port/cpu_start.c b/components/esp_system/port/cpu_start.c
index 752e9eef304..f4fd9e92cfe 100644
--- a/components/esp_system/port/cpu_start.c
+++ b/components/esp_system/port/cpu_start.c
@@ -63,6 +63,7 @@
 #elif CONFIG_IDF_TARGET_ESP32H21
 #include "esp_memprot.h"
 #elif CONFIG_IDF_TARGET_ESP32H4
+#include "soc/lp_aon_reg.h"
 #include "esp_memprot.h"
 #elif CONFIG_IDF_TARGET_ESP32S31
 #endif
@@ -374,6 +375,12 @@ void IRAM_ATTR do_multicore_settings(void)
     restore_app_mmu_from_pro_mmu();
 #endif
 
+#if CONFIG_IDF_TARGET_ESP32H4
+    // Reassign Layer6 memory to ICache1 for multicore apps before enabling
+    // cache settings for the other cores.
+    REG_SET_BIT(LP_AON_SRAM_USAGE_CONF_REG, LP_AON_ICACHE1_USAGE);
+#endif
+
     cache_bus_mask_t cache_bus_mask_core0 = cache_ll_l1_get_enabled_bus(0);
 #ifndef CONFIG_IDF_TARGET_ESP32
     // 1. disable the cache before changing its settings.
@@ -489,6 +496,12 @@ FORCE_INLINE_ATTR IRAM_ATTR void ram_app_init(void)
 //Keep this static, the compiler will check output parameters are initialized.
 FORCE_INLINE_ATTR IRAM_ATTR void ext_mem_init(void)
 {
+#if CONFIG_IDF_TARGET_ESP32H4
+    // Initially assign Layer6 memory to CPU RAM. Multicore startup will
+    // reassign it to ICache1 if the app is not configured for single-core mode.
+    REG_CLR_BIT(LP_AON_SRAM_USAGE_CONF_REG, LP_AON_ICACHE1_USAGE);
+#endif
+
 #if !CONFIG_ESP_SYSTEM_SINGLE_CORE_MODE && !SOC_CACHE_INTERNAL_MEM_VIA_L1CACHE
     // It helps to fix missed cache settings for other cores. It happens when bootloader is unicore.
     do_multicore_settings();
diff --git a/tools/test_apps/system/.build-test-rules.yml b/tools/test_apps/system/.build-test-rules.yml
index 94ab300d305..2927d909d58 100644
--- a/tools/test_apps/system/.build-test-rules.yml
+++ b/tools/test_apps/system/.build-test-rules.yml
@@ -189,7 +189,3 @@ tools/test_apps/system/unicore_bootloader:
       reason: the test is only relevant for multicore chips
     - if: CONFIG_NAME == "unicore_psram" and SOC_PSRAM_SUPPORTED != 1
     - if: CONFIG_NAME == "multicore_psram" and SOC_PSRAM_SUPPORTED != 1
-  disable_test:
-    - if: IDF_TARGET == "esp32h4"
-      temporary: true
-      reason: cannot pass # TODO: IDF-15620
diff --git a/tools/test_apps/system/unicore_bootloader/pytest_unicore_bootloader.py b/tools/test_apps/system/unicore_bootloader/pytest_unicore_bootloader.py
index 6bc4c0cbedf..de5222c79cc 100644
--- a/tools/test_apps/system/unicore_bootloader/pytest_unicore_bootloader.py
+++ b/tools/test_apps/system/unicore_bootloader/pytest_unicore_bootloader.py
@@ -12,7 +12,6 @@ from pytest_embedded_idf.utils import soc_filtered_targets
 @pytest.mark.generic
 @pytest.mark.parametrize('config', ['multicore', 'multicore_psram'], indirect=True)
 @idf_parametrize('target', soc_filtered_targets('SOC_CPU_CORES_NUM > 1'), indirect=['target'])
-@pytest.mark.temp_skip_ci(targets=['esp32h4'], reason='cannot pass')  # TODO: IDF-15620
 def test_multicore_app_and_unicore_bootloader(dut: Dut, app_downloader, config) -> None:  # type: ignore
     dut.expect('Multicore bootloader')
     dut.expect('Multicore app')
@@ -37,7 +36,6 @@ def test_multicore_app_and_unicore_bootloader(dut: Dut, app_downloader, config)
 @pytest.mark.generic
 @pytest.mark.parametrize('config', ['unicore', 'unicore_psram'], indirect=True)
 @idf_parametrize('target', soc_filtered_targets('SOC_CPU_CORES_NUM > 1'), indirect=['target'])
-@pytest.mark.temp_skip_ci(targets=['esp32h4'], reason='cannot pass')  # TODO: IDF-15620
 def test_unicore_app_and_multicore_bootloader(dut: Dut, app_downloader, config) -> None:  # type: ignore
     dut.expect('Unicore bootloader')
     dut.expect('Unicore app')