diff --git a/libraries/AP_HAL_ChibiOS/Util.cpp b/libraries/AP_HAL_ChibiOS/Util.cpp
index 7d56981c5c4c3..3f11aa6696eaf 100644
--- a/libraries/AP_HAL_ChibiOS/Util.cpp
+++ b/libraries/AP_HAL_ChibiOS/Util.cpp
@@ -76,6 +76,12 @@ void* Util::malloc_type(size_t size, AP_HAL::Util::Memory_Type mem_type)
         return malloc_dma(size);
     } else if (mem_type == AP_HAL::Util::MEM_FAST) {
         return malloc_fastmem(size);
+    } else if (mem_type == AP_HAL::Util::MEM_FILESYSTEM) {
+#if defined(STM32H7)
+        return malloc_axi_sram(size);
+#else
+        return malloc_dma(size);
+#endif
     } else {
         return calloc(1, size);
     }
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.c b/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.c
index 590855bd59ed4..f1f735ab8f353 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/bouncebuffer.c
@@ -21,23 +21,6 @@
 #include <stdio.h>
 #include "bouncebuffer.h"
 
-#if defined(STM32H7)
-// always use a bouncebuffer on H7, to ensure alignment and padding
-#define IS_DMA_SAFE(addr) false
-#elif defined(STM32F732xx)
-// always use bounce buffer on F732
-#define IS_DMA_SAFE(addr) false
-#elif defined(STM32F7)
-// on F76x we only consider first half of DTCM memory as DMA safe, 2nd half is used as fast memory for EKF
-// on F74x we only have 64k of DTCM
-#define IS_DMA_SAFE(addr) ((((uint32_t)(addr)) & ((0xFFFFFFFF & ~(64*1024U-1)) | 1U)) == 0x20000000)
-#elif defined(STM32F1)
-#define IS_DMA_SAFE(addr) true
-#else
-// this checks an address is in main memory and 16 bit aligned
-#define IS_DMA_SAFE(addr) ((((uint32_t)(addr)) & 0xF0000001) == 0x20000000)
-#endif
-
 // Enable when trying to check if you are not just listening yourself
 #define ENABLE_ECHO_SAFE 0
 
@@ -64,7 +47,7 @@ void bouncebuffer_init(struct bouncebuffer_t **bouncebuffer, uint32_t prealloc_b
  */
 bool bouncebuffer_setup_read(struct bouncebuffer_t *bouncebuffer, uint8_t **buf, uint32_t size)
 {
-    if (!bouncebuffer || IS_DMA_SAFE(*buf)) {
+    if (!bouncebuffer || mem_is_dma_safe(*buf, size, bouncebuffer->on_axi_sram)) {
         // nothing needs to be done
         return true;
     }
@@ -113,7 +96,7 @@ void bouncebuffer_finish_read(struct bouncebuffer_t *bouncebuffer, const uint8_t
  */
 bool bouncebuffer_setup_write(struct bouncebuffer_t *bouncebuffer, const uint8_t **buf, uint32_t size)
 {
-    if (!bouncebuffer || IS_DMA_SAFE(*buf)) {
+    if (!bouncebuffer || mem_is_dma_safe(*buf, size, bouncebuffer->on_axi_sram)) {
         // nothing needs to be done
         return true;
     }
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/malloc.c b/libraries/AP_HAL_ChibiOS/hwdef/common/malloc.c
index d9b30d5a69379..dada2e1c433c6 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/malloc.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/malloc.c
@@ -616,3 +616,44 @@ void ff_memfree(void* mblock)
     free(mblock);
 }
 #endif // USE_POSIX
+
+/*
+  return true if a memory region is safe for a DMA operation
+ */
+bool mem_is_dma_safe(const void *addr, uint32_t size, bool filesystem_op)
+{
+    (void)filesystem_op;
+#if defined(STM32F1)
+    // F1 is always OK
+    (void)addr;
+    (void)size;
+    return true;
+#else
+    uint32_t flags = MEM_REGION_FLAG_DMA_OK;
+#if defined(STM32H7)
+    if (((uint32_t)addr) & 0x1F) {
+        return false;
+    }
+    if (filesystem_op) {
+        flags = MEM_REGION_FLAG_AXI_BUS;
+    }
+#elif defined(STM32F4)
+    if (((uint32_t)addr) & 0x01) {
+        return false;
+    }
+#else
+    if (((uint32_t)addr) & 0x07) {
+        return false;
+    }
+#endif
+    for (uint8_t i=0; i<NUM_MEMORY_REGIONS; i++) {
+        if (memory_regions[i].flags & flags) {
+            if ((uint32_t)addr >= (uint32_t)memory_regions[i].address &&
+                ((uint32_t)addr + size) <= ((uint32_t)memory_regions[i].address + memory_regions[i].size)) {
+                return true;
+            }
+        }
+    }
+    return false;
+#endif // STM32F1
+}
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
index 0a56342d256fd..5a24edd59fe97 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
@@ -43,6 +43,7 @@ void *malloc_axi_sram(size_t size);
 void *malloc_fastmem(size_t size);
 void *malloc_eth_safe(size_t size);
 thread_t *thread_create_alloc(size_t size, const char *name, tprio_t prio, tfunc_t pf, void *arg);
+bool mem_is_dma_safe(const void *addr, uint32_t size, bool filesystem_op);
 
 struct memory_region {
     void *address;
diff --git a/libraries/AP_HAL_ChibiOS/sdcard.cpp b/libraries/AP_HAL_ChibiOS/sdcard.cpp
index c8cc8dcf7eba8..922440826b06d 100644
--- a/libraries/AP_HAL_ChibiOS/sdcard.cpp
+++ b/libraries/AP_HAL_ChibiOS/sdcard.cpp
@@ -73,7 +73,11 @@ bool sdcard_init()
     if (sdcd.bouncebuffer == nullptr) {
         // allocate 4k bouncebuffer for microSD to match size in
         // AP_Logger
+#if defined(STM32H7)
         bouncebuffer_init(&sdcd.bouncebuffer, 4096, true);
+#else
+        bouncebuffer_init(&sdcd.bouncebuffer, 4096, false);
+#endif
     }
 
     if (sdcard_running) {