# FreeRTOS not running after bootloader jump (SAMC21, app @ 0x8000) **URL:** \ **Category:** Kernel\ **Created:** [April 8, 2025, 9:13am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879 "2025-04-08T09:13:19Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Jeevitha](https://avatars.discourse-cdn.com/v4/letter/j/9dc877/32.png) [@Jeevitha](https://forums.freertos.org/u/Jeevitha)\ **Post date:** [April 8, 2025, 9:13am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/1 "2025-04-08T09:13:19Z")
My FreeRTOS code works perfectly when flashed alone (starts from 0x00000000). When bootloader is flashed first, then application (at 0x00008000), FreeRTOS doesn’t run — it doesn’t enter tasks. FreeRTOS tasks not running after bootloader jump (SAMC21, app at 0x8000) Microcontroller: _SAMC21N18A_ Compiler/IDE: _Atmel Studio_ FreeRTOS version (10) Bootloader used (custom) I’m using a custom bootloader on a SAMC21N18A microcontroller with FreeRTOS. The bootloader starts at 0x00000000 and jumps to the application at 0x00008000. When I flash only the application (starting at 0x00000000), FreeRTOS works fine. But when I flash the bootloader at 0x00000000 and the application at 0x00008000, FreeRTOS doesn’t run — no tasks are executed, and it seems interrupts aren’t firing ➕ ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 8, 2025, 9:17am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/2 "2025-04-08T09:17:38Z")
> [@Jeevitha](#): > > no tasks are executed, and it seems interrupts aren’t firing SAMC21 is a cortex-M device. Have you correctly updated the [VTOR](https://developer.arm.com/documentation/dui0662/b/Cortex-M0--Peripherals/System-Control-Block/Vector-Table-Offset-Register)? This is a good document from ARM describing all the steps needed to write a bootloader - [Documentation – Arm Developer](https://developer.arm.com/documentation/ka002218/latest/). ---
**Author:** ![Jeevitha](https://avatars.discourse-cdn.com/v4/letter/j/9dc877/32.png) [@Jeevitha](https://forums.freertos.org/u/Jeevitha)\ **Post date:** [April 9, 2025, 4:34am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/3 "2025-04-09T04:34:14Z")
but our custom bootloader is working for non-RTOS code, but facing issue with RTOS code ---
**Author:** ![jefftenney](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/jefftenney/32/1314_2.png) [@jefftenney](https://forums.freertos.org/u/jefftenney)\ **Post date:** [April 9, 2025, 4:40am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/4 "2025-04-09T04:40:03Z")
Yes but your RTOS code works fine without the bootloader, right? ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 9, 2025, 5:05am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/5 "2025-04-09T05:05:51Z")
> [@Jeevitha](#): > > but facing issue with RTOS code A very possible reason is that the vector table is not correctly setup because FreeRTOS requires some ISRs to be installed correctly. Did you try my above suggestions? ---
**Author:** ![Jeevitha](https://avatars.discourse-cdn.com/v4/letter/j/9dc877/32.png) [@Jeevitha](https://forums.freertos.org/u/Jeevitha)\ **Post date:** [April 9, 2025, 6:53am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/6 "2025-04-09T06:53:20Z")
Yes, my RTOS code works fine (starts from 0x00000000) ---
**Author:** ![Jeevitha](https://avatars.discourse-cdn.com/v4/letter/j/9dc877/32.png) [@Jeevitha](https://forums.freertos.org/u/Jeevitha)\ **Post date:** [April 9, 2025, 7:14am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/7 "2025-04-09T07:14:43Z")
Vector table is correctly setup, I have configured FreeRTOS version 10 in Atmel Start. What other tools do I need to install for FreeRTOS to work properly? int main(void) { atmel\_start\_init(); Initialization(); // This includes print statements // Task creation for Task 1 to Task 6 vTaskStartScheduler(); } In my FreeRTOS code, I added print statements inside the Initialization() function (which runs outside the RTOS). I can see those print statements through Data Visualizer, so I know it’s being called. However, the tasks are not being created — they are not running. ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 9, 2025, 7:21am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/8 "2025-04-09T07:21:36Z")
> [@Jeevitha](#): > > Vector table is correctly setup, Can you share the code in your bootloader where you do that? ---
**Author:** ![Jeevitha](https://avatars.discourse-cdn.com/v4/letter/j/9dc877/32.png) [@Jeevitha](https://forums.freertos.org/u/Jeevitha)\ **Post date:** [April 9, 2025, 9:35am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/9 "2025-04-09T09:35:51Z")
Sorry, I couldn’t share the code on a public forum ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 9, 2025, 11:20am UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/10 "2025-04-09T11:20:49Z")
In that case, have you done all the steps in the documents I liked above? Are you setting VTOR by doing something like the following: ```auto SCB->VTOR = ( uint32_t )Address ; ``` If the answer to both the questions is yes, can you break the code in debugger and see what it is doing when it appears stuck? ---
**Author:** ![dc42](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/dc42/32/487_2.png) [@dc42](https://forums.freertos.org/u/dc42)\ **Post date:** [April 11, 2025, 3:40pm UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/11 "2025-04-11T15:40:27Z")
We do exactly this on a SAMC21. You can find our code at [Duet3Bootloader/src/Bootloader.cpp at dev · Duet3D/Duet3Bootloader · GitHub](https://github.com/Duet3D/Duet3Bootloader/blob/dev/src/Bootloader.cpp). See in particular the StartFirmware() function at the end. ---
**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\ **Post date:** [April 12, 2025, 9:45pm UTC](https://forums.freertos.org/t/freertos-not-running-after-bootloader-jump-samc21-app-0x8000/22879/12 "2025-04-12T21:45:52Z")
Thank you for sharing @dc42!