the only thing that doesn't work is the buffer, which is bad, but at least the board lights up

memory.x

@@ -1,18 +1,16 @@
-/* Memory layout of the STM32F469NI */
 MEMORY
 {
-    FLASH : ORIGIN = 0x08000000, LENGTH = 2M
-    RAM : ORIGIN = 0x20000000, LENGTH = 384K
-    CCMRAM : ORIGIN = 0x10000000, LENGTH = 64K
-		SDRAM : ORIGIN = 0xC0000000, LENGTH = 16M
+  FLASH : ORIGIN = 0x08000000, LENGTH = 2M
+  RAM : ORIGIN = 0x20000000, LENGTH = 320K
+  SDRAM : ORIGIN = 0xC0000000, LENGTH = 16M
 }
 
 SECTIONS
 {
-    .sdram (NOLOAD) :
-    {
-        *(.sdram .sdram.*);
-    } > SDRAM
+	.sdram (NOLOAD) :
+	{
+			. = ALIGN(4);
+			*(.sdram)
+			. = ALIGN(4);
+	} >SDRAM
 }
-
-_stack_start = ORIGIN(RAM) + LENGTH(RAM);