diff --git a/tools/unit-test-app/README.md b/tools/unit-test-app/README.md
index d3581d023..d59e71f74 100644
--- a/tools/unit-test-app/README.md
+++ b/tools/unit-test-app/README.md
@@ -12,6 +12,12 @@ ESP-IDF unit tests are run using Unit Test App. The app can be built with the un
 * Follow the printed instructions to flash, or run `make flash`.
 * Unit test have a few preset sdkconfigs. It provides command `make ut-clean-config_name` and `make ut-build-config_name` (where `config_name` is the file name under `unit-test-app/configs` folder) to build with preset configs. For example, you can use `make ut-build-default TESTS_ALL=1` to build with config file `unit-test-app/configs/default`. Built binary for this config will be copied to `unit-test-app/output/config_name` folder.
 
+# Flash Size
+
+The unit test partition table assumes a 4MB flash size. When testing `TESTS_ALL=1`, this additional factory app partition size is required.
+
+If building unit tests to run on a smaller flash size, edit `partition_table_unit_tests_app.csv` and use `TEST_COMPONENTS=` instead of `TESTS_ALL` if tests don't fit in a smaller factory app partition (exact size will depend on configured options).
+
 # Running Unit Tests
 
 The unit test loader will prompt by showing a menu of available tests to run:
diff --git a/tools/unit-test-app/partition_table_unit_test_app.csv b/tools/unit-test-app/partition_table_unit_test_app.csv
index 46173719b..5f80c5e79 100644
--- a/tools/unit-test-app/partition_table_unit_test_app.csv
+++ b/tools/unit-test-app/partition_table_unit_test_app.csv
@@ -5,10 +5,12 @@
 nvs,        data, nvs,     0x9000,  0x4000
 otadata,    data, ota,     0xd000,  0x2000
 phy_init,   data, phy,     0xf000,  0x1000
-factory,    0,    0,       0x10000, 0x140000
+factory,    0,    0,       0x10000, 0x240000
 # these OTA partitions are used for tests, but can't fit real OTA apps in them
-# (done this way so tests can run in 2MB of flash.)
+# (done this way to reduce total flash usage.)
 ota_0,      0,    ota_0,   ,        64K
 ota_1,      0,    ota_1,   ,        64K
 # flash_test partition used for SPI flash tests, WL FAT tests, and SPIFFS tests
 flash_test, data, fat,     ,        528K
+
+# Note: still 1MB of a 4MB flash left free for some other purpose
diff --git a/tools/unit-test-app/sdkconfig.defaults b/tools/unit-test-app/sdkconfig.defaults
index e2ca5f433..a9b24b60e 100644
--- a/tools/unit-test-app/sdkconfig.defaults
+++ b/tools/unit-test-app/sdkconfig.defaults
@@ -1,6 +1,6 @@
 CONFIG_LOG_BOOTLOADER_LEVEL_WARN=y
 CONFIG_ESPTOOLPY_BAUD_921600B=y
-CONFIG_ESPTOOLPY_FLASHSIZE_2MB=y
+CONFIG_ESPTOOLPY_FLASHSIZE_4MB=y
 CONFIG_ESPTOOLPY_FLASHSIZE_DETECT=n
 CONFIG_PARTITION_TABLE_CUSTOM=y
 CONFIG_PARTITION_TABLE_CUSTOM_FILENAME="partition_table_unit_test_app.csv"