diff --git a/src/system/boot/arch/m68k/mmu.cpp b/src/system/boot/arch/m68k/mmu.cpp
index cb48df052b..741296b940 100644
--- a/src/system/boot/arch/m68k/mmu.cpp
+++ b/src/system/boot/arch/m68k/mmu.cpp
@@ -668,6 +668,7 @@ platform_free_region(void *address, size_t size)
 ssize_t
 platform_allocate_heap_region(size_t size, void **_base)
 {
+	size = ROUNDUP(size, B_PAGE_SIZE);
 	addr_t base = get_next_physical_address(size);
 	if (base == 0)
 		return B_NO_MEMORY;
diff --git a/src/system/boot/platform/amiga_m68k/mmu.cpp b/src/system/boot/platform/amiga_m68k/mmu.cpp
index 0f12363fbe..d03a7210cf 100644
--- a/src/system/boot/platform/amiga_m68k/mmu.cpp
+++ b/src/system/boot/platform/amiga_m68k/mmu.cpp
@@ -666,6 +666,7 @@ platform_free_region(void *address, size_t size)
 ssize_t
 platform_allocate_heap_region(size_t size, void **_base)
 {
+	size = ROUNDUP(size, B_PAGE_SIZE);
 	addr_t base = get_next_physical_address(size);
 	if (base == 0)
 		return B_NO_MEMORY;
diff --git a/src/system/boot/platform/atari_m68k/mmu.cpp b/src/system/boot/platform/atari_m68k/mmu.cpp
index 438c9cdb94..92fedd80f1 100644
--- a/src/system/boot/platform/atari_m68k/mmu.cpp
+++ b/src/system/boot/platform/atari_m68k/mmu.cpp
@@ -671,6 +671,7 @@ platform_free_region(void *address, size_t size)
 ssize_t
 platform_allocate_heap_region(size_t size, void **_base)
 {
+	size = ROUNDUP(size, B_PAGE_SIZE);
 	addr_t base = get_next_physical_address(size);
 	if (base == 0)
 		return B_NO_MEMORY;
diff --git a/src/system/boot/platform/bios_ia32/mmu.cpp b/src/system/boot/platform/bios_ia32/mmu.cpp
index b070665e97..d61d15a0d6 100644
--- a/src/system/boot/platform/bios_ia32/mmu.cpp
+++ b/src/system/boot/platform/bios_ia32/mmu.cpp
@@ -826,6 +826,7 @@ platform_free_region(void *address, size_t size)
 ssize_t
 platform_allocate_heap_region(size_t size, void **_base)
 {
+	size = ROUNDUP(size, B_PAGE_SIZE);
 	addr_t base = allocate_physical(size, false);
 	if (base == 0)
 		return B_NO_MEMORY;