diff --git a/board/st/common/cmd_stboard.c b/board/st/common/cmd_stboard.c
index 1573e35410..915164aa0b 100644
--- a/board/st/common/cmd_stboard.c
+++ b/board/st/common/cmd_stboard.c
@@ -1,6 +1,32 @@
 // SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause
 /*
  * Copyright (C) 2019, STMicroelectronics - All Rights Reserved
+ *
+ * the st command stboard supports the STMicroelectronics board identification
+ * saved in OTP 59.
+ *
+ * The ST product codification have several element
+ * - "Commercial Product Name" (CPN): type of product board (DKX, EVX)
+ *   associated to the board ID "MBxxxx"
+ * - "Finished Good" or "Finish Good" (FG):
+ *   effective content of the product without chip STM32MP1xx (LCD, Wifi,?)
+ * - BOM: cost variant for same FG (for example, several provider of the same
+ *   component)
+ *
+ * For example
+ * - commercial product = STM32MP157C-EV1 for board MB1263
+ * - Finished Good = EVA32MP157A1$AU1
+ *
+ * Both information are written on board and these information are also saved
+ * in OTP59, with:
+ * bit [31:16] (hex) => Board id, MBxxxx
+ * bit [15:12] (dec) => Variant CPN (1....15)
+ * bit [11:8]  (dec) => Revision board (index with A = 1, Z = 26)
+ * bit [7:4]   (dec) => Variant FG : finished good index
+ * bit [3:0]   (dec) => BOM (01, .... 255)
+ *
+ * and displayed with the format:
+ *   Board: MB<Board> Var<VarCPN>.<VarFG> Rev.<Revision>-<BOM>
  */
 
 #ifndef CONFIG_SPL_BUILD
@@ -13,6 +39,7 @@
 static bool check_stboard(u16 board)
 {
 	unsigned int i;
+	/* list of supported ST boards */
 	const u16 st_board_id[] = {
 		0x1272,
 		0x1263,
@@ -31,9 +58,11 @@ static bool check_stboard(u16 board)
 
 static void display_stboard(u32 otp)
 {
-	printf("Board: MB%04x Var%d Rev.%c-%02d\n",
+	/* display board indentification with OPT coding */
+	printf("Board: MB%04x Var%d.%d Rev.%c-%02d\n",
 	       otp >> 16,
 	       (otp >> 12) & 0xF,
+	       (otp >> 4) & 0xF,
 	       ((otp >> 8) & 0xF) - 1 + 'A',
 	       otp & 0xF);
 }
@@ -44,14 +73,14 @@ static int do_stboard(cmd_tbl_t *cmdtp, int flag, int argc,
 	int ret;
 	u32 otp, lock;
 	u8 revision;
-	unsigned long board, variant, bom;
+	unsigned long board, var_cpn, var_fg, bom;
 	struct udevice *dev;
-	int confirmed = argc == 6 && !strcmp(argv[1], "-y");
+	int confirmed = argc == 7 && !strcmp(argv[1], "-y");
 
 	argc -= 1 + confirmed;
 	argv += 1 + confirmed;
 
-	if (argc != 0 && argc != 4)
+	if (argc != 0 && argc != 5)
 		return CMD_RET_USAGE;
 
 	ret = uclass_get_device_by_driver(UCLASS_MISC,
@@ -95,8 +124,8 @@ static int do_stboard(cmd_tbl_t *cmdtp, int flag, int argc,
 		return CMD_RET_USAGE;
 	}
 
-	if (strict_strtoul(argv[1], 10, &variant) < 0 ||
-	    variant == 0 || variant > 15) {
+	if (strict_strtoul(argv[1], 10, &var_cpn) < 0 ||
+	    var_cpn == 0 || var_cpn > 15) {
 		printf("argument %d invalid: %s\n", 2, argv[1]);
 		return CMD_RET_USAGE;
 	}
@@ -107,13 +136,21 @@ static int do_stboard(cmd_tbl_t *cmdtp, int flag, int argc,
 		return CMD_RET_USAGE;
 	}
 
-	if (strict_strtoul(argv[3], 10, &bom) < 0 ||
+	if (strict_strtoul(argv[3], 10, &var_fg) < 0 ||
+	    var_fg > 15) {
+		printf("argument %d invalid: %s\n", 4, argv[3]);
+		return CMD_RET_USAGE;
+	}
+
+	if (strict_strtoul(argv[4], 10, &bom) < 0 ||
 	    bom == 0 || bom > 15) {
 		printf("argument %d invalid: %s\n", 4, argv[3]);
 		return CMD_RET_USAGE;
 	}
 
-	otp = (board << 16) | (variant << 12) | (revision << 8) | bom;
+	/* st board indentification value */
+	otp = (board << 16) | (var_cpn << 12) | (revision << 8) |
+	      (var_fg << 4) | bom;
 	display_stboard(otp);
 	printf("=> OTP[%d] = %08X\n", BSEC_OTP_BOARD, otp);
 
@@ -153,15 +190,16 @@ static int do_stboard(cmd_tbl_t *cmdtp, int flag, int argc,
 	return CMD_RET_SUCCESS;
 }
 
-U_BOOT_CMD(stboard, 6, 0, do_stboard,
+U_BOOT_CMD(stboard, 7, 0, do_stboard,
 	   "read/write board reference in OTP",
 	   "\n"
 	   "  Print current board information\n"
-	   "stboard [-y] <Board> <Variant> <Revision> <BOM>\n"
+	   "stboard [-y] <Board> <VarCPN> <Revision> <VarFG> <BOM>\n"
 	   "  Write board information\n"
 	   "  - Board: xxxx, example 1264 for MB1264\n"
-	   "  - Variant: 1 ... 15\n"
+	   "  - VarCPN: 1...15\n"
 	   "  - Revision: A...O\n"
+	   "  - VarFG: 0...15\n"
 	   "  - BOM: 1...15\n");
 
 #endif
diff --git a/board/st/stm32mp1/stm32mp1.c b/board/st/stm32mp1/stm32mp1.c
index c36e7655c0..4dd0098c6e 100644
--- a/board/st/stm32mp1/stm32mp1.c
+++ b/board/st/stm32mp1/stm32mp1.c
@@ -104,6 +104,7 @@ int checkboard(void)
 		printf(" (%s)", fdt_compat);
 	puts("\n");
 
+	/* display the STMicroelectronics board identification */
 	ret = uclass_get_device_by_driver(UCLASS_MISC,
 					  DM_GET_DRIVER(stm32mp_bsec),
 					  &dev);
@@ -112,9 +113,10 @@ int checkboard(void)
 		ret = misc_read(dev, STM32_BSEC_SHADOW(BSEC_OTP_BOARD),
 				&otp, sizeof(otp));
 	if (ret > 0 && otp) {
-		printf("Board: MB%04x Var%d Rev.%c-%02d\n",
+		printf("Board: MB%04x Var%d.%d Rev.%c-%02d\n",
 		       otp >> 16,
 		       (otp >> 12) & 0xF,
+		       (otp >> 4) & 0xF,
 		       ((otp >> 8) & 0xF) - 1 + 'A',
 		       otp & 0xF);
 	}
