diff --git a/82802ab.c b/82802ab.c
index 608995d..2a43813 100644
--- a/82802ab.c
+++ b/82802ab.c
@@ -89,6 +89,7 @@
 	return 1;
 }
 
+/* FIXME: needs timeout */
 uint8_t wait_82802ab(struct flashctx *flash)
 {
 	uint8_t status;
diff --git a/Makefile b/Makefile
index b7315a4..bd536f0 100644
--- a/Makefile
+++ b/Makefile
@@ -320,7 +320,7 @@
 ###############################################################################
 # Flash chip drivers and bus support infrastructure.
 
-CHIP_OBJS = jedec.o stm50flw0x0x.o w39.o w29ee011.o \
+CHIP_OBJS = jedec.o stm50.o w39.o w29ee011.o \
 	sst28sf040.o m29f400bt.o 82802ab.o pm49fl00x.o \
 	sst49lfxxxc.o sst_fwhub.o flashchips.o spi.o spi25.o spi25_statusreg.o \
 	opaque.o sfdp.o en29lv640b.o at45db.o
diff --git a/chipdrivers.h b/chipdrivers.h
index 180d36d..851e90a 100644
--- a/chipdrivers.h
+++ b/chipdrivers.h
@@ -193,9 +193,10 @@
 /* w29ee011.c */
 int probe_w29ee011(struct flashctx *flash);
 
-/* stm50flw0x0x.c */
-int erase_sector_stm50flw0x0x(struct flashctx *flash, unsigned int block, unsigned int blocksize);
-int unlock_stm50flw0x0x(struct flashctx *flash);
+/* stm50.c */
+int erase_sector_stm50(struct flashctx *flash, unsigned int block, unsigned int blocksize);
+int unlock_stm50_uniform(struct flashctx *flash);
+int unlock_stm50_nonuniform(struct flashctx *flash);
 
 /* en29lv640b.c */
 int probe_en29lv640b(struct flashctx *flash);
diff --git a/flashchips.c b/flashchips.c
index 83855fc..396f026 100644
--- a/flashchips.c
+++ b/flashchips.c
@@ -11008,7 +11008,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50FLW040A,
 		.total_size	= 512,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_UNTESTED,
 		.probe		= probe_82802ab,
@@ -11028,8 +11028,8 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
 		.write		= write_82802ab,
+		.unlock		= unlock_stm50_uniform,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
 	},
@@ -11041,7 +11041,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50FLW040B,
 		.total_size	= 512,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_UNTESTED,
 		.probe		= probe_82802ab,
@@ -11061,8 +11061,8 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
 		.write		= write_82802ab,
+		.unlock		= unlock_stm50_uniform,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
 	},
@@ -11074,7 +11074,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50FLW080A,
 		.total_size	= 1024,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_OK_PRE,
 		.probe		= probe_82802ab,
@@ -11094,7 +11094,7 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
+		.unlock		= unlock_stm50_nonuniform,
 		.write		= write_82802ab,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
@@ -11107,7 +11107,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50FLW080B,
 		.total_size	= 1024,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_UNTESTED,
 		.probe		= probe_82802ab,
@@ -11127,7 +11127,7 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
+		.unlock		= unlock_stm50_nonuniform,
 		.write		= write_82802ab,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
@@ -11140,7 +11140,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50FW002,
 		.total_size	= 256,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_UNTESTED,
 		.probe		= probe_82802ab,
@@ -11157,7 +11157,7 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
+		.unlock		= unlock_stm50_nonuniform,
 		.write		= write_82802ab,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
@@ -11170,7 +11170,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50FW016,
 		.total_size	= 2048,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_UNTESTED,
 		.probe		= probe_82802ab,
@@ -11182,7 +11182,7 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
+		.unlock		= unlock_stm50_uniform,
 		.write		= write_82802ab,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
@@ -11195,7 +11195,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50FW040,
 		.total_size	= 512,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_OK_PR,
 		.probe		= probe_82802ab,
@@ -11207,7 +11207,7 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
+		.unlock		= unlock_stm50_uniform,
 		.write		= write_82802ab,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
@@ -11220,7 +11220,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50FW080,
 		.total_size	= 1024,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_OK_PREW,
 		.probe		= probe_82802ab,
@@ -11232,7 +11232,7 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
+		.unlock		= unlock_stm50_uniform,
 		.write		= write_82802ab,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
@@ -11245,7 +11245,7 @@
 		.manufacture_id	= ST_ID,
 		.model_id	= ST_M50LPW116,
 		.total_size	= 2048,
-		.page_size	= 64 * 1024,
+		.page_size	= 0,
 		.feature_bits	= FEATURE_REGISTERMAP,
 		.tested		= TEST_UNTESTED,
 		.probe		= probe_82802ab,
@@ -11263,7 +11263,7 @@
 				.block_erase = erase_block_82802ab,
 			}
 		},
-		.unlock		= unlock_stm50flw0x0x,
+		.unlock		= unlock_stm50_nonuniform,
 		.write		= write_82802ab,
 		.read		= read_memmapped,
 		.voltage	= {3000, 3600}, /* Also has 12V fast program & erase */
diff --git a/stm50.c b/stm50.c
new file mode 100644
index 0000000..26bd6ed
--- /dev/null
+++ b/stm50.c
@@ -0,0 +1,103 @@
+/*
+ * This file is part of the flashrom project.
+ *
+ * Copyright (C) 2008 Claus Gindhart <claus.gindhart@kontron.com>
+ * Copyright (C) 2009 Sean Nelson <audiohacked@gmail.com>
+ * Copyright (C) 2013 Stefan Tauner
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+/*
+ * All ST M50 chips are locked on startup. Most of them have a uniform 64 kB block layout, but some have
+ * a non-uniform block/sector segmentation which has to be handled with more care. Some of the non-uniform
+ * chips support erasing of the 4 kB sectors with another command.
+ */
+
+#include "flash.h"
+#include "flashchips.h"
+#include "chipdrivers.h"
+
+static int stm50_unlock_address(struct flashctx *flash, int offset)
+{
+	chipaddr wrprotect = flash->virtual_registers + 2;
+	static const uint8_t unlock_sector = 0x00;
+	msg_cdbg("unlocking at 0x%x\n", offset);
+	chip_writeb(flash, unlock_sector, wrprotect + offset);
+	if (chip_readb(flash, wrprotect + offset) != unlock_sector) {
+		msg_cerr("Cannot unlock address 0x%x\n", offset);
+		return -1;
+	}
+	return 0;
+}
+
+/* Chips known to use a non-uniform block and sector layout for locking (as well as for erasing):
+ * Name		Size	Address range of lock registers
+ * M50FLW080A	1MB 	FFB00002 - FFBFF002
+ * M50FLW080B	1MB	FFB00002 - FFBFF002
+ * M50FW002	256k	FFBC0002 - FFBFC002
+ * M50LPW116	2MB	FFA00002 - FFBFC002
+ */
+int unlock_stm50_nonuniform(struct flashctx *flash)
+{
+	int i;
+	struct eraseblock *eraseblocks = flash->chip->block_erasers[0].eraseblocks;
+	unsigned int done = 0;
+	for (i = 0; i < NUM_ERASEREGIONS && eraseblocks[i].count != 0; i++) {
+		unsigned int block_size = eraseblocks[i].size;
+		unsigned int block_count = eraseblocks[i].count;
+
+		int j;
+		for (j = 0; j < block_count; j++) {
+			if (stm50_unlock_address(flash, done)) {
+				msg_cerr("UNLOCK FAILED!\n");
+				return -1;
+			}
+			done += block_count * block_size;
+		}
+	}
+	return 0;
+}
+
+/* Unlocking for uniform 64 kB blocks starting at offset 2 of the feature registers. */
+int unlock_stm50_uniform(struct flashctx *flash)
+{
+	int i;
+	for (i = 0; i < flash->chip->total_size * 1024; i+= 64 * 1024) {
+		if (stm50_unlock_address(flash, i)) {
+			msg_cerr("UNLOCK FAILED!\n");
+			return -1;
+		}
+	}
+	return 0;
+}
+
+/* This function is unused. */
+int erase_sector_stm50(struct flashctx *flash, unsigned int sector, unsigned int sectorsize)
+{
+	chipaddr bios = flash->virtual_memory + sector;
+
+	// clear status register
+	chip_writeb(flash, 0x50, bios);
+	// now start it
+	chip_writeb(flash, 0x32, bios);
+	chip_writeb(flash, 0xd0, bios);
+	programmer_delay(10);
+
+	wait_82802ab(flash);
+
+	/* FIXME: Check the status register for errors. */
+	return 0;
+}
diff --git a/stm50flw0x0x.c b/stm50flw0x0x.c
deleted file mode 100644
index e6c7c05..0000000
--- a/stm50flw0x0x.c
+++ /dev/null
@@ -1,115 +0,0 @@
-/*
- * This file is part of the flashrom project.
- *
- * Copyright (C) 2008 Claus Gindhart <claus.gindhart@kontron.com>
- * Copyright (C) 2009 Sean Nelson <audiohacked@gmail.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
- */
-
-/*
- * This module is designed for supporting the devices
- * ST M50FLW040A (not yet tested)
- * ST M50FLW040B (not yet tested)
- * ST M50FLW080A
- * ST M50FLW080B (not yet tested)
- */
-
-#include "flash.h"
-#include "flashchips.h"
-#include "chipdrivers.h"
-
-/*
- * claus.gindhart@kontron.com
- * The ST M50FLW080B and STM50FLW080B chips have to be unlocked,
- * before you can erase them or write to them.
- */
-static int unlock_block_stm50flw0x0x(struct flashctx *flash, int offset)
-{
-	chipaddr wrprotect = flash->virtual_registers + 2;
-	static const uint8_t unlock_sector = 0x00;
-	int j;
-
-	/*
-	 * These chips have to be unlocked before you can erase them or write
-	 * to them. The size of the locking sectors depends on the type
-	 * of chip.
-	 *
-	 * Sometimes, the BIOS does this for you; so you probably
-	 * don't need to worry about that.
-	 */
-
-	/* Check, if it's is a top/bottom-block with 4k-sectors. */
-	/* TODO: What about the other types? */
-	if ((offset == 0) ||
-	    (offset == (flash->chip->model_id == ST_M50FLW080A ? 0xE0000 : 0x10000))
-	    || (offset == 0xF0000)) {
-
-		// unlock each 4k-sector
-		for (j = 0; j < 0x10000; j += 0x1000) {
-			msg_cdbg("unlocking at 0x%x\n", offset + j);
-			chip_writeb(flash, unlock_sector,
-				    wrprotect + offset + j);
-			if (chip_readb(flash, wrprotect + offset + j) !=
-			    unlock_sector) {
-				msg_cerr("Cannot unlock sector @ 0x%x\n",
-				       offset + j);
-				return -1;
-			}
-		}
-	} else {
-		msg_cdbg("unlocking at 0x%x\n", offset);
-		chip_writeb(flash, unlock_sector, wrprotect + offset);
-		if (chip_readb(flash, wrprotect + offset) != unlock_sector) {
-			msg_cerr("Cannot unlock sector @ 0x%x\n", offset);
-			return -1;
-		}
-	}
-
-	return 0;
-}
-
-int unlock_stm50flw0x0x(struct flashctx *flash)
-{
-	int i;
-
-	for (i = 0; i < flash->chip->total_size * 1024; i+= flash->chip->page_size) {
-		if(unlock_block_stm50flw0x0x(flash, i)) {
-			msg_cerr("UNLOCK FAILED!\n");
-			return -1;
-		}
-	}
-
-	return 0;
-}
-
-/* This function is unused. */
-int erase_sector_stm50flw0x0x(struct flashctx *flash, unsigned int sector,
-			      unsigned int sectorsize)
-{
-	chipaddr bios = flash->virtual_memory + sector;
-
-	// clear status register
-	chip_writeb(flash, 0x50, bios);
-	// now start it
-	chip_writeb(flash, 0x32, bios);
-	chip_writeb(flash, 0xd0, bios);
-	programmer_delay(10);
-
-	wait_82802ab(flash);
-
-	/* FIXME: Check the status register for errors. */
-	return 0;
-}