Add SD Card check & Folder/file check

docs/Error-Codes.md

@@ -26,6 +26,41 @@ This usually is because on of the following reasons:
  - The camera is not attached properly -> Try to remove and attach it again. Make sure you move the black part enough into the socket!
  - The camera or the camera cable is damaged
 
+## `0x00000008` SD card basic check failed
+One or more basic SD card checks failed.
+
+The following checks are performed during boot sequence:
+- Write a file (sdcard/sdcheck.txt) to SD card with some generic text
+- Read the written file back
+- CRC check
+- Delete the file
+
+Detailed error indication (write, rerad or delete error) can be derived from blinking code of red board status LED. Please have a look to !!!TODO!!!
+
+Recommendation: Reformat SD card and check again or try another SD card
+
+## `0x00000010` SD folder or file presence check failed
+Oned or more mandatory folders and/or files are missing on SD card.
+To have early indication that SD card is potentially ready for operation, some folder and files, which are mandatory are presence checked. This is not a 100% check and a successful test does not mean everthing is OK.
+
+The following folders / files get checked during boot sequence:
+- /sdcard/config
+- /sdcard/html
+- /sdcard/demo --> created automatically in firmware
+- /sdcard/firmware --> created automatically in firmware
+- /sdcard/img_tmp --> created automatically in firmware
+- /sdcard/log --> created automatically in firmware
+- /sdcard/wlan.ini
+- /sdcard/config/config.ini
+- /sdcard/html/index.html
+- /sdcard/html/ota_page.html
+- /sdcard/html/log.html
+- /sdcard/html/common.js
+- /sdcard/html/gethost.js
+- /sdcard/html/version.txt
+
+Recommendation: Check logs and / or redo a Over-The-Air Update (OTA Update) to ensure proper SD card structure
+
 # Non-Critical Errors
 Those Errors can be caused by an error during initialization. It is possible that the error has no impact at all or that a reboot solves it.