Add Chunk2 and Chunk4 support.

Even using the interpolator, I can't make 640 chunky4 pixels fit in the time available - it visibly glitches.

Author: thejpster

memory.x

@@ -25,18 +25,18 @@ MEMORY {
     /*
      * This is the bottom of the four striped banks of SRAM in the RP2040.
      */
-    RAM_OS : ORIGIN = 0x20000000, LENGTH = 0x42000 - 0x9090
+    RAM_OS : ORIGIN = 0x20000000, LENGTH = 0x42000 - 0x9300
     /*
      * This is the top of the four striped banks of SRAM in the RP2040, plus
      * SRAM_BANK4 and SRAM_BANK5.
      *
      * This is carefully calculated to give us 8 KiB of stack space and ensure
      * the defmt buffer doesn't span across SRAM_BANK3 and SRAM_BANK4.
      *
-     * 0x9090 should be the (size of .data + size of .bss + size of .uninit +
+     * 0x9300 should be the (size of .data + size of .bss + size of .uninit +
      * 0x2000 for the stack).
      */
-    RAM : ORIGIN = 0x20042000 - 0x9090, LENGTH = 0x9090
+    RAM : ORIGIN = 0x20042000 - 0x9300, LENGTH = 0x9300
 }
 
 /*