X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/de9d05f32a8f6ea8e10f601bcbb0bcbcea0975d1..31022dfbe9ba7f10e9be5be85e16d2ee203d40df:/Bootloaders/CDC/BootloaderCDC.txt?ds=sidebyside diff --git a/Bootloaders/CDC/BootloaderCDC.txt b/Bootloaders/CDC/BootloaderCDC.txt index 29bfd78f3..337b6e4a5 100644 --- a/Bootloaders/CDC/BootloaderCDC.txt +++ b/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 THIS BOOTLOADER IS NOT SECURE. 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 @@ -117,6 +120,12 @@ * #define BOOTLOADER_ADDRESS_LENGTH 4 * \endcode * + * From the application the API support of the bootloader can be detected by reading the FLASH memory bytes located at address + * \c BOOTLOADER_MAGIC_SIGNATURE_START and comparing them to the value \c BOOTLOADER_MAGIC_SIGNATURE. The class of bootloader + * can be determined by reading the FLASH memory bytes located at address \c BOOTLOADER_CLASS_SIGNATURE_START and comparing them + * to the value \c BOOTLOADER_CDC_SIGNATURE. The start address of the bootloader can be retrieved by reading the bytes of FLASH + * memory starting from address \c BOOTLOADER_ADDRESS_START. + * * \subsection SSec_API_MemLayout Device Memory Map * The following illustration indicates the final memory map of the device when loaded with the bootloader. * @@ -155,11 +164,25 @@ * +----------------------------+ FLASHEND * \endverbatim * - * Bootloaders reporting a device release revision number of 1.00 or greater are bootloader API enabled. From the application - * the API support of the bootloader can be detected by reading the FLASH memory bytes located at address \c BOOTLOADER_MAGIC_SIGNATURE_START - * and comparing them to the value \c BOOTLOADER_MAGIC_SIGNATURE. The class of bootloader can be determined by reading the - * FLASH memory bytes located at address \c BOOTLOADER_CLASS_SIGNATURE_START and comparing them to the value \c BOOTLOADER_CDC_SIGNATURE. - * The start address of the bootloader can be retrieved by reading the bytes of FLASH memory starting from address \c BOOTLOADER_ADDRESS_START. + * \section Sec_KnownIssues Known Issues: + * + * \par On Linux machines, the CDC bootloader is unstable or inaccessible. + * A change to the \c ModemManager module in many Linux distributions causes + * this module to try to take control over inserted CDC devices, corrupting the + * datastream. A UDEV rule is required to prevent this. + * See here for resolution steps. + * + * \par On Linux machines, the CDC bootloader is inaccessible. + * On many Linux systems, non-root users do not have automatic access to newly + * inserted CDC devices. Root privileges or a UDEV rule is required to gain + * access. + * See here for resolution steps. + * + * \par After loading an application, it is not run automatically on startup. + * Some USB AVR boards ship with the BOOTRST fuse set, causing the bootloader + * to run automatically when the device is reset. In most cases, the BOOTRST + * fuse should be disabled and the HWBE fuse used instead to run the bootloader + * when needed. * * \section Sec_Options Project Options * @@ -167,9 +190,9 @@ * * * - * - * - * + * + * + * * * *
Define Name:Location:Description:Define Name:Location:Description:
NO_BLOCK_SUPPORT