diff --git a/flash.h b/flash.h
index 80c129c..c77522d 100644
--- a/flash.h
+++ b/flash.h
@@ -144,8 +144,10 @@
 #define FEATURE_ERASED_ZERO	(1 << 17)
 #define FEATURE_NO_ERASE	(1 << 18)
 
-#define FEATURE_WRSR_EXT	(1 << 19)
+#define FEATURE_WRSR_EXT2	(1 << 19)
 #define FEATURE_WRSR2		(1 << 20)
+#define FEATURE_WRSR_EXT3	((1 << 21) | FEATURE_WRSR_EXT2)
+#define FEATURE_WRSR3		(1 << 22)
 
 #define ERASED_VALUE(flash)	(((flash)->chip->feature_bits & FEATURE_ERASED_ZERO) ? 0x00 : 0xff)
 
diff --git a/flashchips.c b/flashchips.c
index 95bbcba..5cb71a8 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -6296,7 +6296,7 @@
 		.total_size	= 16384,
 		.page_size	= 256,
 		/* OTP: 1024B total, 256B reserved; read 0x48; write 0x42, erase 0x44 */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_WRSR_EXT,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_WRSR_EXT2,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,
@@ -6462,7 +6462,7 @@
 		.total_size	= 8192,
 		.page_size	= 256,
 		/* OTP: 1024B total, 256B reserved; read 0x48; write 0x42, erase 0x44 */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_WRSR_EXT,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_WRSR_EXT2,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,
@@ -6716,7 +6716,7 @@
 		.total_size	= 32768,
 		.page_size	= 256,
 		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_4BA_WREN |
-				  FEATURE_WRSR_EXT | FEATURE_WRSR2,
+				  FEATURE_WRSR_EXT2 | FEATURE_WRSR2 | FEATURE_WRSR3,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,
@@ -16963,7 +16963,8 @@
 		.page_size	= 256,
 		/* supports SFDP */
 		/* OTP: 1024B total, 256B reserved; read 0x48; write 0x42, erase 0x44, read ID 0x4B */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_WRSR2,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP |
+				  FEATURE_WRSR_EXT2 | FEATURE_WRSR2 | FEATURE_WRSR3,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,
@@ -17854,7 +17855,8 @@
 		.page_size	= 256,
 		/* supports SFDP */
 		/* OTP: 1024B total, 256B reserved; read 0x48; write 0x42, erase 0x44, read ID 0x4B */
-		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP | FEATURE_WRSR2,
+		.feature_bits	= FEATURE_WRSR_WREN | FEATURE_OTP |
+				  FEATURE_WRSR_EXT2 | FEATURE_WRSR2 | FEATURE_WRSR3,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_spi_rdid,
 		.probe_timing	= TIMING_ZERO,
diff --git a/spi.h b/spi.h
index 2992312..80385fa 100644
--- a/spi.h
+++ b/spi.h
@@ -150,7 +150,6 @@
 #define JEDEC_WRSR		0x01
 #define JEDEC_WRSR_OUTSIZE	0x02
 #define JEDEC_WRSR_INSIZE	0x00
-#define JEDEC_WRSR_EXT_OUTSIZE	0x03
 
 /* Write Status Register 2 */
 #define JEDEC_WRSR2		0x31
diff --git a/spi25_statusreg.c b/spi25_statusreg.c
index 0f43056..5dbba75 100644
--- a/spi25_statusreg.c
+++ b/spi25_statusreg.c
@@ -22,11 +22,44 @@
 #include "spi.h"
 
 /* === Generic functions === */
+
+/*
+ * Writing SR2 or higher with an extended WRSR command requires
+ * writing all lower SRx along with it, so just read the lower
+ * SRx and write them back.
+ */
+static int spi_prepare_wrsr_ext(
+		uint8_t write_cmd[4], size_t *const write_cmd_len,
+		const struct flashctx *const flash,
+		const enum flash_reg reg, const uint8_t value)
+{
+	enum flash_reg reg_it;
+	size_t i = 0;
+
+	write_cmd[i++] = JEDEC_WRSR;
+
+	for (reg_it = STATUS1; reg_it < reg; ++reg_it) {
+		uint8_t sr;
+
+		if (spi_read_register(flash, reg_it, &sr)) {
+			msg_cerr("Writing SR%d failed: failed to read SR%d for writeback.\n",
+				 reg - STATUS1 + 1, reg_it - STATUS1 + 1);
+			return 1;
+		}
+		write_cmd[i++] = sr;
+	}
+
+	write_cmd[i++] = value;
+	*write_cmd_len = i;
+
+	return 0;
+}
+
 int spi_write_register(const struct flashctx *flash, enum flash_reg reg, uint8_t value)
 {
 	int feature_bits = flash->chip->feature_bits;
 
-	uint8_t write_cmd[3];
+	uint8_t write_cmd[4];
 	size_t write_cmd_len = 0;
 
 	/*
@@ -46,31 +79,27 @@
 			write_cmd_len = JEDEC_WRSR2_OUTSIZE;
 			break;
 		}
-		if (feature_bits & FEATURE_WRSR_EXT) {
-			/*
-			 * Writing SR2 with an extended WRSR command requires
-			 * writing SR1 along with SR2, so just read SR1 and
-			 * write it back
-			 */
-			uint8_t sr1;
-
-			if (spi_read_register(flash, STATUS1, &sr1)) {
-				msg_cerr("Writing SR2 failed: failed to read SR1 for writeback.\n");
+		if (feature_bits & FEATURE_WRSR_EXT2) {
+			if (spi_prepare_wrsr_ext(write_cmd, &write_cmd_len, flash, reg, value))
 				return 1;
-			}
-			write_cmd[0] = JEDEC_WRSR;
-			write_cmd[1] = sr1;
-			write_cmd[2] = value;
-			write_cmd_len = JEDEC_WRSR_EXT_OUTSIZE;
 			break;
 		}
 		msg_cerr("Cannot write SR2: unsupported by chip\n");
 		return 1;
 	case STATUS3:
-		write_cmd[0] = JEDEC_WRSR3;
-		write_cmd[1] = value;
-		write_cmd_len = JEDEC_WRSR3_OUTSIZE;
-		break;
+		if (feature_bits & FEATURE_WRSR3) {
+			write_cmd[0] = JEDEC_WRSR3;
+			write_cmd[1] = value;
+			write_cmd_len = JEDEC_WRSR3_OUTSIZE;
+			break;
+		}
+		if ((feature_bits & FEATURE_WRSR_EXT3) == FEATURE_WRSR_EXT3) {
+			if (spi_prepare_wrsr_ext(write_cmd, &write_cmd_len, flash, reg, value))
+				return 1;
+			break;
+		}
+		msg_cerr("Cannot write SR3: unsupported by chip\n");
+		return 1;
 	default:
 		msg_cerr("Cannot write register: unknown register\n");
 		return 1;
@@ -152,15 +181,20 @@
 		read_cmd = JEDEC_RDSR;
 		break;
 	case STATUS2:
-		if (feature_bits & (FEATURE_WRSR_EXT | FEATURE_WRSR2)) {
+		if (feature_bits & (FEATURE_WRSR_EXT2 | FEATURE_WRSR2)) {
 			read_cmd = JEDEC_RDSR2;
 			break;
 		}
 		msg_cerr("Cannot read SR2: unsupported by chip\n");
 		return 1;
 	case STATUS3:
-		read_cmd = JEDEC_RDSR3;
-		break;
+		if ((feature_bits & FEATURE_WRSR_EXT3) == FEATURE_WRSR_EXT3
+		    || (feature_bits & FEATURE_WRSR3)) {
+			read_cmd = JEDEC_RDSR3;
+			break;
+		}
+		msg_cerr("Cannot read SR3: unsupported by chip\n");
+		return 1;
 	default:
 		msg_cerr("Cannot read register: unknown register\n");
 		return 1;