8 files changed, 6 insertions, 2 deletions
diff --git a/cortex-m-rt/asm.s b/cortex-m-rt/asm.s
index 7a36197..1cb310a 100644
--- a/cortex-m-rt/asm.s
+++ b/cortex-m-rt/asm.s
@@ -60,12 +60,16 @@ FpuTrampoline:
   .cfi_startproc
 PreResetTrampoline:
   # set LR to the initial value used by the ARMv7-M (0xFFFF_FFFF)
-  ldr r0,=0xffffffff
-  mov lr,r0
+  ldr r4,=0xffffffff
+  mov lr,r4
 
   # run the pre-init code
   bl __pre_init
 
+  # the call above clobbers LR, but tools may expect LR to be 0xFFFFFFFF when reaching the first
+  # call frame, so we restore it to its previous value (r4 is preserved by subroutines)
+  mov lr,r4
+
   # initialize .data and .bss memory
   ldr r0,=__sbss
   ldr r1,=__ebss
diff --git a/cortex-m-rt/bin/thumbv6m-none-eabi.a b/cortex-m-rt/bin/thumbv6m-none-eabi.a
index 674b34a..207dad2 100644
--- a/cortex-m-rt/bin/thumbv6m-none-eabi.a
+++ b/cortex-m-rt/bin/thumbv6m-none-eabi.a
diff --git a/cortex-m-rt/bin/thumbv7em-none-eabi.a b/cortex-m-rt/bin/thumbv7em-none-eabi.a
index a0302b1..18509c1 100644
--- a/cortex-m-rt/bin/thumbv7em-none-eabi.a
+++ b/cortex-m-rt/bin/thumbv7em-none-eabi.a
diff --git a/cortex-m-rt/bin/thumbv7em-none-eabihf.a b/cortex-m-rt/bin/thumbv7em-none-eabihf.a
index a0302b1..18509c1 100644
--- a/cortex-m-rt/bin/thumbv7em-none-eabihf.a
+++ b/cortex-m-rt/bin/thumbv7em-none-eabihf.a
diff --git a/cortex-m-rt/bin/thumbv7m-none-eabi.a b/cortex-m-rt/bin/thumbv7m-none-eabi.a
index 0298e64..59fdb28 100644
--- a/cortex-m-rt/bin/thumbv7m-none-eabi.a
+++ b/cortex-m-rt/bin/thumbv7m-none-eabi.a
diff --git a/cortex-m-rt/bin/thumbv8m.base-none-eabi.a b/cortex-m-rt/bin/thumbv8m.base-none-eabi.a
index 8a3cfcf..4c28721 100644
--- a/cortex-m-rt/bin/thumbv8m.base-none-eabi.a
+++ b/cortex-m-rt/bin/thumbv8m.base-none-eabi.a
diff --git a/cortex-m-rt/bin/thumbv8m.main-none-eabi.a b/cortex-m-rt/bin/thumbv8m.main-none-eabi.a
index 02bcf02..5a23da5 100644
--- a/cortex-m-rt/bin/thumbv8m.main-none-eabi.a
+++ b/cortex-m-rt/bin/thumbv8m.main-none-eabi.a
diff --git a/cortex-m-rt/bin/thumbv8m.main-none-eabihf.a b/cortex-m-rt/bin/thumbv8m.main-none-eabihf.a
index 02bcf02..5a23da5 100644
--- a/cortex-m-rt/bin/thumbv8m.main-none-eabihf.a
+++ b/cortex-m-rt/bin/thumbv8m.main-none-eabihf.a