Corrected documentation on SPI FLASH memory usage after SPIFFS area e…

…xtension.
giovanni69 · Dec 29, 2024 · adadfb7 · adadfb7
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Showing 3 changed files with 18 additions and 10 deletions.
diff --git a/client/src/scripting.c b/client/src/scripting.c
@@ -283,7 +283,7 @@ static int l_GetFromFlashMemSpiffs(lua_State *L) {
         return returnToLuaWithError(L, "No FLASH MEM support");
     }
 
-    uint32_t start_index = 0, len = 0x40000;  // 256kb FLASH_MEM_MAX_SIZE as default value
+    uint32_t start_index = 0, len = 0x40000;  // 256KB FLASH_MEM_MAX_SIZE as default value
     char destfilename[32] = {0};
     size_t size;
 

diff --git a/doc/ext_flash_notes.md b/doc/ext_flash_notes.md
@@ -19,7 +19,7 @@ External 256kbytes flash is a unique feature of the RDV4 edition.
 
 Flash memory is
 
-* 256KB (0x40000= 262144)
+* 256KB (0x40000 = 262144)
 * divided into 4 pages of 64KB (0x10000 = 65536)
 * 4 pages divided into 16 sectors of 4KB (0x1000 = 4096), so last sector is at 0x3F000
 
@@ -31,6 +31,8 @@ Therefore a flash address can be interpreted as such:
     ^^^ offset         ^^^ offset 0xF7F
 ```
 
+Please note that for other flash memory sizes than 256KB a "Page 3" will be the last page of the memory, and address offsets would be dependant on the memory size.
+
 ## Layout
 ^[Top](#top)
 
@@ -49,7 +51,7 @@ Page 2:
 * to dump it: `mem dump -f page2_dump -o 131072 -l 65536`
 * to erase it: `mem wipe -p 2`
 
-Page 3:
+Page 3 (or the last page for memories other than 256KB):
 * used by Proxmark3 RDV4 specific functions: flash signature, see below for details
 * to dump it: `mem dump -f page3_dump -o 196608 -l 65536`
 * to erase it:
@@ -60,13 +62,19 @@ Page 3:
 ## Page3 Layout
 ^[Top](#top)
 
-Page3 is used as follows by the Proxmark3 RDV4 firmware:
+Page3 (or the last page for memories other than 256KB) is used as follows by the Proxmark3 RDV4 firmware:
 
 * **RSA SIGNATURE**, see below for details
   * offset: page 3 sector 15 (0xF) offset 0xF7F @ 3*0x10000+15*0x1000+0xF7F=0x3FF7F  (decimal 262015)
   * length: 128 bytes
   * offset should have been 0x3FF80 but historically it's one byte off and therefore the last byte of the flash is unused
 
+* **Reserved for future use**
+  * offset: page 3 sector 14 (0xE)
+
+* **SPIFFS sectors**
+  * offset: page 3 sectors 13..0 (0xD..0x0)
+
 ## RSA signature
 ^[Top](#top)
 

diff --git a/include/pmflash.h b/include/pmflash.h
@@ -22,17 +22,17 @@
 #include "common.h"
 
 // RDV40 Section
-// 256kb divided into 4k sectors.
+// 256KB divided into 4K sectors.
 // +--------+-------------+---------+--------------------------+
-// | Sector | 256kb addr* |  Size   | Description              |
+// | Sector | 256KB addr* |  Size   | Description              |
 // +--------+-------------+---------+--------------------------+
-// | N      |   0x3F000   | 1 * 4kb | signature                |
-// | N-1    |   0x3E000   | 1 * 4kb | reserved for future use  |
+// | N      |   0x3F000   | 1 * 4KB | signature                |
+// | N-1    |   0x3E000   | 1 * 4KB | reserved for future use  |
 // +--------+-------------+---------+--------------------------+
 //
-// * For different memory size than 256kb the address is not valid.
+// * For different memory size than 256KB the address is not valid.
 //   Please instead refer to Sector number, where N is the last
-//   4kb secotr of the memory in question.
+//   4KB secotr of the memory in question.
 
 #ifndef FLASH_MEM_BLOCK_SIZE
 # define FLASH_MEM_BLOCK_SIZE   256