diff --git a/thirdparty/fatfs/ff.c b/thirdparty/fatfs/ff.c
index 7f56871..4a1a2bf 100644
--- a/thirdparty/fatfs/ff.c
+++ b/thirdparty/fatfs/ff.c
@@ -1884,7 +1884,7 @@
 	for (wc = 1, s = 0; s < 13; s++) {		/* Process all characters in the entry */
 		uc = ld_word(dir + LfnOfs[s]);		/* Pick an LFN character */
 		if (wc != 0) {
-			if (i >= FF_MAX_LFN || ff_wtoupper(uc) != ff_wtoupper(lfnbuf[i++])) {	/* Compare it */
+			if (i >= FF_MAX_LFN + 1 || ff_wtoupper(uc) != ff_wtoupper(lfnbuf[i++])) {	/* Compare it */
 				return 0;					/* Not matched */
 			}
 			wc = uc;
@@ -1920,15 +1920,15 @@
 	for (wc = 1, s = 0; s < 13; s++) {		/* Process all characters in the entry */
 		uc = ld_word(dir + LfnOfs[s]);		/* Pick an LFN character */
 		if (wc != 0) {
-			if (i >= FF_MAX_LFN) return 0;	/* Buffer overflow? */
+			if (i >= FF_MAX_LFN + 1) return 0;	/* Buffer overflow? */
 			lfnbuf[i++] = wc = uc;			/* Store it */
 		} else {
 			if (uc != 0xFFFF) return 0;		/* Check filler */
 		}
 	}
 
-	if (dir[LDIR_Ord] & LLEF) {				/* Put terminator if it is the last LFN part */
-		if (i >= FF_MAX_LFN) return 0;		/* Buffer overflow? */
+	if (dir[LDIR_Ord] & LLEF && wc != 0) {	/* Put terminator if it is the last LFN part and not terminated */
+		if (i >= FF_MAX_LFN + 1) return 0;	/* Buffer overflow? */
 		lfnbuf[i] = 0;
 	}
 
@@ -2649,6 +2649,7 @@
 {
 	UINT si, di;
 #if FF_USE_LFN
+	BYTE lcf;
 	WCHAR wc, hs;
 	FATFS *fs = dp->obj.fs;
 #else
@@ -2709,9 +2710,10 @@
 		if (di == 0) {	/* If LFN and SFN both are invalid, this object is inaccesible */
 			fno->fname[di++] = '?';
 		} else {
-			for (si = di = 0; fno->altname[si]; si++, di++) {	/* Copy altname[] to fname[] with case information */
+			for (si = di = 0, lcf = NS_BODY; fno->altname[si]; si++, di++) {	/* Copy altname[] to fname[] with case information */
 				wc = (WCHAR)fno->altname[si];
-				if (IsUpper(wc) && (dp->dir[DIR_NTres] & ((si >= 9) ? NS_EXT : NS_BODY))) wc += 0x20;
+				if (wc == '.') lcf = NS_EXT;
+				if (IsUpper(wc) && (dp->dir[DIR_NTres] & lcf)) wc += 0x20;
 				fno->fname[di] = (TCHAR)wc;
 			}
 		}
@@ -4162,10 +4164,10 @@
 	TCHAR *tp = buff;
 #if FF_VOLUMES >= 2
 	UINT vl;
-#endif
 #if FF_STR_VOLUME_ID
 	const char *vp;
 #endif
+#endif
 	FILINFO fno;
 	DEF_NAMBUF
 
@@ -5642,7 +5644,7 @@
 		b_fat = b_vol + 32;										/* FAT start at offset 32 */
 		sz_fat = ((sz_vol / au + 2) * 4 + ss - 1) / ss;			/* Number of FAT sectors */
 		b_data = (b_fat + sz_fat + sz_blk - 1) & ~(sz_blk - 1);	/* Align data area to the erase block boundary */
-		if (b_data >= sz_vol / 2) LEAVE_MKFS(FR_MKFS_ABORTED);	/* Too small volume? */
+		if (b_data - b_vol >= sz_vol / 2) LEAVE_MKFS(FR_MKFS_ABORTED);	/* Too small volume? */
 		n_clst = (sz_vol - (b_data - b_vol)) / au;				/* Number of clusters */
 		if (n_clst <16) LEAVE_MKFS(FR_MKFS_ABORTED);			/* Too few clusters? */
 		if (n_clst > MAX_EXFAT) LEAVE_MKFS(FR_MKFS_ABORTED);	/* Too many clusters? */