diff --git a/lib/oofatfs/ffunicode.c b/lib/oofatfs/ffunicode.c
index 26ac738507..a04577616a 100644
--- a/lib/oofatfs/ffunicode.c
+++ b/lib/oofatfs/ffunicode.c
@@ -499,7 +499,7 @@ DWORD ff_wtoupper ( /* Returns up-converted code point */
     DWORD uni       /* Unicode code point to be up-converted */
 )
 {
-    #if FF_FS_ASCII_UPPER_ONLY
+    #if FF_FS_CASE_INSENSITIVE_COMPARISON_ASCII_ONLY
     // Only uppercase ASCII characters. Everything else will require the user to
     // pass in an uppercase version.
     if ('a' <= uni && uni <= 'z') {
diff --git a/ports/unix/mpconfigport.h b/ports/unix/mpconfigport.h
index c54fede813..c94845229c 100644
--- a/ports/unix/mpconfigport.h
+++ b/ports/unix/mpconfigport.h
@@ -178,6 +178,9 @@
 #define MICROPY_FATFS_RPATH            (2)
 #define MICROPY_FATFS_MAX_SS           (4096)
 #define MICROPY_FATFS_LFN_CODE_PAGE    437 /* 1=SFN/ANSI 437=LFN/U.S.(OEM) */
+#define MICROPY_FATFS_LFN_UNICODE      (2)
+
+#define FF_FS_CASE_INSENSITIVE_COMPARISON_ASCII_ONLY         (1)
 
 // Define to MICROPY_ERROR_REPORTING_DETAILED to get function, etc.
 // names in exception messages (may require more RAM).
diff --git a/py/circuitpy_mpconfig.h b/py/circuitpy_mpconfig.h
index 6b9ded9294..a514b6a160 100644
--- a/py/circuitpy_mpconfig.h
+++ b/py/circuitpy_mpconfig.h
@@ -595,7 +595,7 @@ void supervisor_run_background_tasks_if_tick(void);
 #define CIRCUITPY_DIGITALIO_HAVE_INVALID_DRIVE_MODE (0)
 #endif
 
-#define FF_FS_ASCII_UPPER_ONLY (1)
+#define FF_FS_CASE_INSENSITIVE_COMPARISON_ASCII_ONLY (1)
 
 #define FF_FS_MAKE_VOLID (1)
 
diff --git a/tests/extmod/vfs_fat_case.py b/tests/extmod/vfs_fat_case.py
index 45496dcf81..40d67da9b8 100644
--- a/tests/extmod/vfs_fat_case.py
+++ b/tests/extmod/vfs_fat_case.py
@@ -51,18 +51,29 @@ vfs = uos.VfsFat(bdev)
 uos.mount(vfs, "/ramdisk")
 uos.chdir("/ramdisk")
 
+vfs.label = "labelæ"
+# This label would normally be LABELÆ but our limited upper casing does "LABELæ"
+print(vfs.label)
+
 # Check ASCII case-insensitivity
-vfs.mkdir("foo_dir_az")
+vfs.mkdir("fooaz")
 print(uos.listdir(""))
-vfs.rmdir("fOO_dir_AZ")
+vfs.rmdir("fOOAZ")
+
+# Check ASCII case-insensitivity for long names (8+ characters)
+vfs.mkdir("123456789fooaz")
+print(uos.listdir(""))
+vfs.rmdir("123456789fOOAZ")
 
 # Characters outside of a-z are case sensitive.
 vfs.mkdir("extended_æ")
 print(uos.listdir(""))
+# Normally this would work ok. With our limited uppercasing, it won't.
 try:
     vfs.rmdir("extended_Æ")
 except OSError as e:
     print(e.errno == uerrno.ENOENT)
+
 vfs.rmdir("extended_æ")
 
 # Emoji test for fun.
diff --git a/tests/extmod/vfs_fat_case.py.exp b/tests/extmod/vfs_fat_case.py.exp
index 0089bc9b51..64b5e7b27a 100644
--- a/tests/extmod/vfs_fat_case.py.exp
+++ b/tests/extmod/vfs_fat_case.py.exp
@@ -1,3 +1,5 @@
-['foo_dir_az']
+LABELæ
+['fooaz']
+['123456789fooaz']
 ['extended_æ']
 True