diff --git a/flash.h b/flash.h
index 1fd864b..9d88742 100644
--- a/flash.h
+++ b/flash.h
@@ -72,7 +72,7 @@
 
 #define EON_ID			0x1C
 /* EN25 chips are SPI, first byte of device id is memory type,
-   second byte of device id is log(bitsize)-9 */
+ * second byte of device id is log(bitsize)-9. */
 #define EN_25B05		0x2010	/* 2^19 kbit or 2^16 kByte */
 #define EN_25B10		0x2011
 #define EN_25B20		0x2012
@@ -82,9 +82,8 @@
 #define EN_25B32		0x2016
 
 #define MX_ID			0xC2	/* Macronix (MX) */
-#define MX_29F002		0xB0
-/* MX25L chips are SPI, first byte of device id is memory type,
-   second byte of device id is log(bitsize)-9 */
+/* MX25 chips are SPI, first byte of device id is memory type,
+ * second byte of device id is log(bitsize)-9. */
 #define MX_25L512		0x2010	/* 2^19 kbit or 2^16 kByte */
 #define MX_25L1005		0x2011
 #define MX_25L2005		0x2012
@@ -95,11 +94,22 @@
 #define MX_25L6405		0x2017	/* MX25L3205{,D} */
 #define MX_25L1635D		0x2415
 #define MX_25L3235D		0x2416
+#define MX_29F002		0xB0
 
 #define SHARP_ID		0xB0	/* Sharp */
 #define SHARP_LHF00L04		0xCF
 
 #define SST_ID			0xBF	/* SST */
+/* SST25 chips are SPI, first byte of device id is memory type, second
+ * byte of device id is related to log(bitsize) at least for some chips. */
+#define SST_25WF512		0x2501
+#define SST_25WF010		0x2502
+#define SST_25WF020		0x2503
+#define SST_25WF040		0x2504
+#define SST_25VF016B		0x2541
+#define SST_25VF032B		0x254A
+#define SST_25VF040B		0x258D
+#define SST_25VF080B		0x258E
 #define SST_29EE020A		0x10
 #define SST_28SF040		0x04
 #define SST_39SF010		0xB5
@@ -210,7 +220,7 @@
 /* spi.c */
 int probe_spi(struct flashchip *flash);
 int it87xx_probe_spi_flash(const char *name);
-int generic_spi_command(unsigned char writecnt, unsigned char readcnt, const unsigned char *writearr, unsigned char *readarr);
+int generic_spi_command(unsigned int writecnt, unsigned int readcnt, const unsigned char *writearr, unsigned char *readarr);
 void generic_spi_write_enable();
 void generic_spi_write_disable();
 int generic_spi_chip_erase(struct flashchip *flash);
diff --git a/flashchips.c b/flashchips.c
index d1b471a..6ed9a8c 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -36,7 +36,7 @@
 	 probe_jedec,	erase_chip_jedec, write_jedec},
 	{"At29C020",	ATMEL_ID,	AT_29C020,	256, 256,
 	 probe_jedec,	erase_chip_jedec, write_jedec},
-	{"Mx29f002",	MX_ID,		MX_29F002,	256, 64 * 1024,
+	{"MX29F002",	MX_ID,		MX_29F002,	256, 64 * 1024,
 	 probe_29f002,	erase_29f002, 	write_29f002},
 	{"MX25L4005",	MX_ID,		MX_25L4005,	512, 4 * 1024,
 	 probe_spi,	generic_spi_chip_erase,	generic_spi_chip_write},
diff --git a/spi.c b/spi.c
index 26c0d4a..8467664 100644
--- a/spi.c
+++ b/spi.c
@@ -45,17 +45,31 @@
 #define JEDEC_WRDI_OUTSIZE	0x01
 #define JEDEC_WRDI_INSIZE	0x00
 
-/* Both Chip Erase commands below should work */
-/* Chip Erase 0x60 */
+/* Chip Erase 0x60 is supported by Macronix/SST chips. */
 #define JEDEC_CE_1	{0x60};
 #define JEDEC_CE_1_OUTSIZE	0x01
 #define JEDEC_CE_1_INSIZE	0x00
 
-/* Chip Erase 0xc7 */
+/* Chip Erase 0xc7 is supported by EON/Macronix chips. */
 #define JEDEC_CE_2	{0xc7};
 #define JEDEC_CE_2_OUTSIZE	0x01
 #define JEDEC_CE_2_INSIZE	0x00
 
+/* Block Erase 0x52 is supported by SST chips. */
+#define JEDEC_BE_1	{0x52};
+#define JEDEC_BE_1_OUTSIZE	0x04
+#define JEDEC_BE_1_INSIZE	0x00
+
+/* Block Erase 0xd8 is supported by EON/Macronix chips. */
+#define JEDEC_BE_2	{0xd8};
+#define JEDEC_BE_2_OUTSIZE	0x04
+#define JEDEC_BE_2_INSIZE	0x00
+
+/* Sector Erase 0x20 is supported by Macronix/SST chips. */
+#define JEDEC_SE	{0x20};
+#define JEDEC_SE_OUTSIZE	0x04
+#define JEDEC_SE_INSIZE	0x00
+
 /* Read Status Register */
 #define JEDEC_RDSR	{0x05};
 #define JEDEC_RDSR_OUTSIZE	0x01
@@ -144,7 +158,7 @@
    whereas the IT8716F splits commands internally into address and non-address
    commands with the address in inverse wire order. That's why the register
    ordering in case 4 and 5 may seem strange. */
-static int it8716f_spi_command(uint16_t port, unsigned char writecnt, unsigned char readcnt, const unsigned char *writearr, unsigned char *readarr)
+static int it8716f_spi_command(uint16_t port, unsigned int writecnt, unsigned int readcnt, const unsigned char *writearr, unsigned char *readarr)
 {
 	uint8_t busy, writeenc;
 	int i;
@@ -188,7 +202,7 @@
 		return 1;
 	}
 	/* Start IO, 33MHz, readcnt input bytes, writecnt output bytes. Note:
-	 * We can't use writecnt directly, but have to use a strange encoding 
+	 * We can't use writecnt directly, but have to use a strange encoding.
 	 */ 
 	outb((0x5 << 4) | ((readcnt & 0x3) << 2) | (writeenc), port);
 	do {
@@ -202,7 +216,7 @@
 	return 0;
 }
 
-int generic_spi_command(unsigned char writecnt, unsigned char readcnt, const unsigned char *writearr, unsigned char *readarr)
+int generic_spi_command(unsigned int writecnt, unsigned int readcnt, const unsigned char *writearr, unsigned char *readarr)
 {
 	if (it8716f_flashport)
 		return it8716f_spi_command(it8716f_flashport, writecnt, readcnt, writearr, readarr);
@@ -269,13 +283,58 @@
 
 	generic_spi_write_enable();
 	/* Send CE (Chip Erase) */
-	generic_spi_command(1, 0, cmd, NULL);
-	/* Wait until the Write-In-Progress bit is cleared */
+	generic_spi_command(JEDEC_CE_2_OUTSIZE, JEDEC_CE_2_INSIZE, cmd, NULL);
+	/* Wait until the Write-In-Progress bit is cleared.
+	 * This usually takes 1-85 s, so wait in 1 s steps.
+	 */
 	while (generic_spi_read_status_register() & JEDEC_RDSR_BIT_WIP)
 		sleep(1);
 	return 0;
 }
 
+/* Block size is usually
+ * 64k for Macronix
+ * 32k for SST
+ * 4-32k non-uniform for EON
+ */
+int generic_spi_block_erase(const struct flashchip *flash, unsigned long addr)
+{
+	unsigned char cmd[JEDEC_BE_2_OUTSIZE] = JEDEC_BE_2;
+
+	cmd[1] = (addr & 0x00ff0000) >> 16;
+	cmd[2] = (addr & 0x0000ff00) >> 8;
+	cmd[3] = (addr & 0x000000ff);
+	generic_spi_write_enable();
+	/* Send BE (Block Erase) */
+	generic_spi_command(JEDEC_BE_2_OUTSIZE, JEDEC_BE_2_INSIZE, cmd, NULL);
+	/* Wait until the Write-In-Progress bit is cleared.
+	 * This usually takes 100-4000 ms, so wait in 100 ms steps.
+	 */
+	while (generic_spi_read_status_register() & JEDEC_RDSR_BIT_WIP)
+		usleep(100 * 1000);
+	return 0;
+}
+
+/* Sector size is usually 4k, though Macronix eliteflash has 64k */
+int generic_spi_sector_erase(const struct flashchip *flash, unsigned long addr)
+{
+	unsigned char cmd[JEDEC_SE_OUTSIZE] = JEDEC_SE;
+	cmd[1] = (addr & 0x00ff0000) >> 16;
+	cmd[2] = (addr & 0x0000ff00) >> 8;
+	cmd[3] = (addr & 0x000000ff);
+
+	generic_spi_write_enable();
+	/* Send SE (Sector Erase) */
+	generic_spi_command(JEDEC_SE_OUTSIZE, JEDEC_SE_INSIZE, cmd, NULL);
+	/* Wait until the Write-In-Progress bit is cleared.
+	 * This usually takes 15-800 ms, so wait in 10 ms steps.
+	 */
+	while (generic_spi_read_status_register() & JEDEC_RDSR_BIT_WIP)
+		usleep(10 * 1000);
+	return 0;
+}
+
+/* Page size is usually 256 bytes */
 void it8716f_spi_page_program(int block, uint8_t *buf, uint8_t *bios) {
 	int i;
 
@@ -286,7 +345,9 @@
 		bios[256 * block + i] = buf[256 * block + i];
 	}
 	outb(0, it8716f_flashport);
-	/* Wait until the Write-In-Progress bit is cleared */
+	/* Wait until the Write-In-Progress bit is cleared.
+	 * This usually takes 1-10 ms, so wait in 1 ms steps.
+	 */
 	while (generic_spi_read_status_register() & JEDEC_RDSR_BIT_WIP)
 		usleep(1000);
 }