diff --git a/hw/ppc/ppc440_bamboo.c b/hw/ppc/ppc440_bamboo.c
index da777ef9c2..7e3bc0ec7f 100644
--- a/hw/ppc/ppc440_bamboo.c
+++ b/hw/ppc/ppc440_bamboo.c
@@ -158,7 +158,6 @@ static void main_cpu_reset(void *opaque)
 
 static void bamboo_init(MachineState *machine)
 {
-    ram_addr_t ram_size = machine->ram_size;
     const char *kernel_filename = machine->kernel_filename;
     const char *kernel_cmdline = machine->kernel_cmdline;
     const char *initrd_filename = machine->initrd_filename;
@@ -203,10 +202,8 @@ static void bamboo_init(MachineState *machine)
     /* SDRAM controller */
     memset(ram_bases, 0, sizeof(ram_bases));
     memset(ram_sizes, 0, sizeof(ram_sizes));
-    ram_size = ppc4xx_sdram_adjust(ram_size, PPC440EP_SDRAM_NR_BANKS,
-                                   ram_memories,
-                                   ram_bases, ram_sizes,
-                                   ppc440ep_sdram_bank_sizes);
+    ppc4xx_sdram_banks(machine->ram_size, PPC440EP_SDRAM_NR_BANKS, ram_memories,
+                       ram_bases, ram_sizes, ppc440ep_sdram_bank_sizes);
     /* XXX 440EP's ECC interrupts are on UIC1, but we've only created UIC0. */
     ppc4xx_sdram_init(env, pic[14], PPC440EP_SDRAM_NR_BANKS, ram_memories,
                       ram_bases, ram_sizes, 1);
@@ -268,7 +265,7 @@ static void bamboo_init(MachineState *machine)
     /* Load initrd. */
     if (initrd_filename) {
         initrd_size = load_image_targphys(initrd_filename, RAMDISK_ADDR,
-                                          ram_size - RAMDISK_ADDR);
+                                          machine->ram_size - RAMDISK_ADDR);
 
         if (initrd_size < 0) {
             error_report("could not load ram disk '%s' at %x",
@@ -279,7 +276,7 @@ static void bamboo_init(MachineState *machine)
 
     /* If we're loading a kernel directly, we must load the device tree too. */
     if (kernel_filename) {
-        if (bamboo_load_device_tree(FDT_ADDR, ram_size, RAMDISK_ADDR,
+        if (bamboo_load_device_tree(FDT_ADDR, machine->ram_size, RAMDISK_ADDR,
                                     initrd_size, kernel_cmdline) < 0) {
             error_report("couldn't load device tree");
             exit(1);
diff --git a/hw/ppc/ppc4xx_devs.c b/hw/ppc/ppc4xx_devs.c
index c2e50138aa..d89008a2a4 100644
--- a/hw/ppc/ppc4xx_devs.c
+++ b/hw/ppc/ppc4xx_devs.c
@@ -668,21 +668,22 @@ void ppc4xx_sdram_init (CPUPPCState *env, qemu_irq irq, int nbanks,
 
 /* Fill in consecutive SDRAM banks with 'ram_size' bytes of memory.
  *
- * sdram_bank_sizes[] must be 0-terminated.
+ * sdram_bank_sizes[] must be in descending order, that is sizes[i] > sizes[i+1]
+ * and must be 0-terminated.
  *
  * The 4xx SDRAM controller supports a small number of banks, and each bank
  * must be one of a small set of sizes. The number of banks and the supported
  * sizes varies by SoC. */
-ram_addr_t ppc4xx_sdram_adjust(ram_addr_t ram_size, int nr_banks,
-                               MemoryRegion ram_memories[],
-                               hwaddr ram_bases[],
-                               hwaddr ram_sizes[],
-                               const ram_addr_t sdram_bank_sizes[])
+void ppc4xx_sdram_banks(ram_addr_t ram_size, int nr_banks,
+                        MemoryRegion ram_memories[],
+                        hwaddr ram_bases[], hwaddr ram_sizes[],
+                        const ram_addr_t sdram_bank_sizes[])
 {
     MemoryRegion *ram = g_malloc0(sizeof(*ram));
     ram_addr_t size_left = ram_size;
     ram_addr_t base = 0;
     ram_addr_t bank_size;
+    int last_bank = 0;
     int i;
     int j;
 
@@ -690,7 +691,12 @@ ram_addr_t ppc4xx_sdram_adjust(ram_addr_t ram_size, int nr_banks,
         for (j = 0; sdram_bank_sizes[j] != 0; j++) {
             bank_size = sdram_bank_sizes[j];
             if (bank_size <= size_left) {
+                ram_bases[i] = base;
+                ram_sizes[i] = bank_size;
+                base += bank_size;
                 size_left -= bank_size;
+                last_bank = i;
+                break;
             }
         }
         if (!size_left) {
@@ -699,34 +705,32 @@ ram_addr_t ppc4xx_sdram_adjust(ram_addr_t ram_size, int nr_banks,
         }
     }
 
-    ram_size -= size_left;
     if (size_left) {
-        error_report("Truncating memory to %" PRId64 " MiB to fit SDRAM"
-                     " controller limits", ram_size / MiB);
+        ram_addr_t used_size = ram_size - size_left;
+        GString *s = g_string_new(NULL);
+
+        for (i = 0; sdram_bank_sizes[i]; i++) {
+            g_string_append_printf(s, "%" PRIi64 "%s",
+                                   sdram_bank_sizes[i] / MiB,
+                                   sdram_bank_sizes[i + 1] ? " ," : "");
+        }
+        error_report("Max %d banks of %s MB DIMM/bank supported",
+            nr_banks, s->str);
+        error_report("Possible valid RAM size: %" PRIi64,
+            used_size ? used_size / MiB : sdram_bank_sizes[i - 1] / MiB);
+
+        g_string_free(s, true);
+        exit(EXIT_FAILURE);
     }
 
     memory_region_allocate_system_memory(ram, NULL, "ppc4xx.sdram", ram_size);
 
-    size_left = ram_size;
-    for (i = 0; i < nr_banks && size_left; i++) {
-        for (j = 0; sdram_bank_sizes[j] != 0; j++) {
-            bank_size = sdram_bank_sizes[j];
-
-            if (bank_size <= size_left) {
-                char name[32];
-                snprintf(name, sizeof(name), "ppc4xx.sdram%d", i);
-                memory_region_init_alias(&ram_memories[i], NULL, name, ram,
-                                         base, bank_size);
-                ram_bases[i] = base;
-                ram_sizes[i] = bank_size;
-                base += bank_size;
-                size_left -= bank_size;
-                break;
-            }
-        }
+    for (i = 0; i <= last_bank; i++) {
+        char name[32];
+        snprintf(name, sizeof(name), "ppc4xx.sdram%d", i);
+        memory_region_init_alias(&ram_memories[i], NULL, name, ram,
+                                 ram_bases[i], ram_sizes[i]);
     }
-
-    return ram_size;
 }
 
 /*****************************************************************************/
diff --git a/hw/ppc/sam460ex.c b/hw/ppc/sam460ex.c
index 89bc70eb94..17d40bd672 100644
--- a/hw/ppc/sam460ex.c
+++ b/hw/ppc/sam460ex.c
@@ -324,9 +324,8 @@ static void sam460ex_init(MachineState *machine)
     /* SDRAM controller */
     /* put all RAM on first bank because board has one slot
      * and firmware only checks that */
-    machine->ram_size = ppc4xx_sdram_adjust(machine->ram_size, 1,
-                                   ram_memories, ram_bases, ram_sizes,
-                                   ppc460ex_sdram_bank_sizes);
+    ppc4xx_sdram_banks(machine->ram_size, 1, ram_memories, ram_bases, ram_sizes,
+                       ppc460ex_sdram_bank_sizes);
 
     /* FIXME: does 460EX have ECC interrupts? */
     ppc440_sdram_init(env, SDRAM_NR_BANKS, ram_memories,
diff --git a/include/hw/ppc/ppc4xx.h b/include/hw/ppc/ppc4xx.h
index 7d82259051..b8c8f324b4 100644
--- a/include/hw/ppc/ppc4xx.h
+++ b/include/hw/ppc/ppc4xx.h
@@ -42,11 +42,10 @@ enum {
 qemu_irq *ppcuic_init (CPUPPCState *env, qemu_irq *irqs,
                        uint32_t dcr_base, int has_ssr, int has_vr);
 
-ram_addr_t ppc4xx_sdram_adjust(ram_addr_t ram_size, int nr_banks,
-                               MemoryRegion ram_memories[],
-                               hwaddr ram_bases[],
-                               hwaddr ram_sizes[],
-                               const ram_addr_t sdram_bank_sizes[]);
+void ppc4xx_sdram_banks(ram_addr_t ram_size, int nr_banks,
+                        MemoryRegion ram_memories[],
+                        hwaddr ram_bases[], hwaddr ram_sizes[],
+                        const ram_addr_t sdram_bank_sizes[]);
 
 void ppc4xx_sdram_init (CPUPPCState *env, qemu_irq irq, int nbanks,
                         MemoryRegion ram_memories[],