Add security warnings to the documentation of bootloaders without secure writes.

Bootloaders/CDC/BootloaderCDC.txt

@@ -54,6 +54,9 @@
  *  When the bootloader is running, the board's LED(s) will flash at regular intervals to distinguish the
  *  bootloader from the normal user application.
  *
+ *  \warning <b>THIS BOOTLOADER IS NOT SECURE.</b> Malicious entities can recover written data, even if the device
+ *           lockbits are set.
+ *
  *  \section Sec_Installation Driver Installation
  *
  *  After running this bootloader for the first time on a new computer, you will need to supply the .INF

Bootloaders/HID/BootloaderHID.txt

@@ -56,6 +56,9 @@
  *  all other models. If you wish to alter this size and/or change the AVR model, you will need to edit the MCU,
  *  FLASH_SIZE_KB and BOOT_SECTION_SIZE_KB values in the accompanying makefile.
  *
+ *  \warning <b>THIS BOOTLOADER IS NOT SECURE.</b> Malicious entities can recover written data, even if the device
+ *           lockbits are set.
+ *
  *  \section Sec_Installation Driver Installation
  *
  *  This bootloader uses the HID class driver inbuilt into all modern operating systems, thus no additional drivers

Bootloaders/MassStorage/BootloaderMassStorage.txt

@@ -57,6 +57,9 @@
  *  When the bootloader is running, the board's LED(s) will flash at regular intervals to distinguish the
  *  bootloader from the normal user application.
  *
+ *  \warning <b>THIS BOOTLOADER IS NOT SECURE.</b> Malicious entities can recover written data, even if the device
+ *           lockbits are set.
+ *
  *  \section Sec_Installation Driver Installation
  *
  *  This bootloader uses the Mass Storage drivers inbuilt into all modern operating systems, thus no additional