diff --git a/flashloaders/Makefile b/flashloaders/Makefile
index 68ce5a8..73080c6 100644
--- a/flashloaders/Makefile
+++ b/flashloaders/Makefile
@@ -30,6 +30,11 @@ stm32f0.o: stm32f0.s
 stm32vl.o: stm32f0.s
 	$(CC) stm32f0.s $(CFLAGS_ARMV7_M) -o stm32vl.o
 
+# separate rule for STM32Lx.
+# Built for ARMv6-M target to be compatible with both Cortex M0 and Cortex M3.
+stm32lx.o: stm32lx.s
+	$(CC) stm32lx.s $(CFLAGS_ARMV6_M) -o stm32lx.o
+
 # generic rule for all other ARMv7-M
 %.o: %.s
 	$(CC) $< $(CFLAGS_ARMV7_M) -o $@
diff --git a/flashloaders/stm32lx.s b/flashloaders/stm32lx.s
index 69acdea..263f1f8 100644
--- a/flashloaders/stm32lx.s
+++ b/flashloaders/stm32lx.s
@@ -17,8 +17,8 @@ loop:
     str r4, [r1]
 
     # increment address
-    add r0, r0, #4
-    add r1, r1, #4
+    adds r0, r0, #4
+    adds r1, r1, #4
 
     # loop if count > 0
     subs r2, r2, #4
diff --git a/src/stlink-lib/flash_loader.c b/src/stlink-lib/flash_loader.c
index 0ab8cf6..040a7ab 100644
--- a/src/stlink-lib/flash_loader.c
+++ b/src/stlink-lib/flash_loader.c
@@ -68,12 +68,12 @@ static const uint8_t loader_code_stm32f0[] = {
     0x14, 0x00, 0x00, 0x00
 };
 
-// flashloaders/stm32lx.s
+// flashloaders/stm32lx.s -- compiled for armv6-m for compatibility with both
+// armv6-m cores (STM32L0) and armv7-m cores (STM32L1)
 static const uint8_t loader_code_stm32lx[] = {
     0x04, 0x68, 0x0c, 0x60,
-    0x00, 0xf1, 0x04, 0x00,
-    0x01, 0xf1, 0x04, 0x01,
-    0x04, 0x3a, 0xf7, 0xdc,
+    0x04, 0x30, 0x04, 0x31,
+    0x04, 0x3a, 0xf9, 0xdc,
     0x00, 0xbe, 0x00, 0x00
 };
 
@@ -428,12 +428,11 @@ int32_t stlink_flash_loader_run(stlink_t *sl, flash_loader_t* fl, stm32_addr_t t
 #define L1_WRITE_BLOCK_SIZE 0x80
 #define L0_WRITE_BLOCK_SIZE 0x40
 
-int32_t stm32l1_write_half_pages(stlink_t *sl, stm32_addr_t addr, uint8_t *base, uint32_t len, uint32_t pagesize) {
+int32_t stm32l1_write_half_pages(stlink_t *sl, flash_loader_t *fl, stm32_addr_t addr, uint8_t *base, uint32_t len, uint32_t pagesize) {
   uint32_t count, off;
   uint32_t num_half_pages = len / pagesize;
   uint32_t val;
   uint32_t flash_regs_base = get_stm32l0_flash_base(sl);
-  flash_loader_t fl;
   bool use_loader = true;
   int32_t ret = 0;
 
@@ -448,7 +447,7 @@ int32_t stm32l1_write_half_pages(stlink_t *sl, stm32_addr_t addr, uint8_t *base,
 
   for (count = 0; count < num_half_pages; count++) {
     if (use_loader) {
-      ret = stlink_flash_loader_run(sl, &fl, addr + count * pagesize, base + count * pagesize, pagesize);
+      ret = stlink_flash_loader_run(sl, fl, addr + count * pagesize, base + count * pagesize, pagesize);
       if (ret && count == 0) {
         /* It seems that stm32lx devices have a problem when it is blank */
         WLOG("Failed to use flash loader, fallback to soft write\n");
@@ -770,7 +769,7 @@ int32_t stlink_flashloader_write(stlink_t *sl, flash_loader_t *fl, stm32_addr_t
     off = 0;
 
     if (len > pagesize) {
-      if (stm32l1_write_half_pages(sl, addr, base, len, pagesize)) {
+      if (stm32l1_write_half_pages(sl, fl, addr, base, len, pagesize)) {
         return (-1);
       } else {
         off = (size_t)(len / pagesize) * pagesize;
diff --git a/src/stlink-lib/flash_loader.h b/src/stlink-lib/flash_loader.h
index 33edc7a..6ac2e4f 100644
--- a/src/stlink-lib/flash_loader.h
+++ b/src/stlink-lib/flash_loader.h
@@ -18,7 +18,7 @@ int32_t stlink_flash_loader_run(stlink_t *sl, flash_loader_t* fl, stm32_addr_t t
 
 /* === Functions from old header file flashloader.h === */
 
-int32_t stm32l1_write_half_pages(stlink_t *sl, stm32_addr_t addr, uint8_t *base, uint32_t len, uint32_t pagesize);
+int32_t stm32l1_write_half_pages(stlink_t *sl, flash_loader_t *fl, stm32_addr_t addr, uint8_t *base, uint32_t len, uint32_t pagesize);
 // static void set_flash_cr_pg(stlink_t *sl, uint32_t bank);
 // static void set_dma_state(stlink_t *sl, flash_loader_t *fl, int32_t bckpRstr);
 int32_t stlink_flashloader_start(stlink_t *sl, flash_loader_t *fl);