stm: allow more flash for the binary.

stm/stm32f405.ld

@@ -7,7 +7,7 @@ MEMORY
 {
     FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 0x100000 /* entire flash, 1 MiB */
     FLASH_ISR (rx)  : ORIGIN = 0x08000000, LENGTH = 0x004000 /* sector 0, 16 KiB */
-    FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 0x020000 /* sector 5, 128 KiB */
+    FLASH_TEXT (rx) : ORIGIN = 0x08020000, LENGTH = 0x080000 /* sectors 5,6,7,8, 4*128KiB = 512 KiB (could increase it more) */
     CCMRAM (xrw)    : ORIGIN = 0x10000000, LENGTH = 0x010000 /* 64 KiB */
     RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 0x020000 /* 128 KiB */
 }