Bootswapping operation is very unstable, even more in release

Hi everyone,

Context of the project

I'm working on a bootloader project based on RL78. I set my memory like this : 

This idea is to jump from application to bootloader when I want to update the application and to jump from bootloader to application when I'm finished with the upload.

Major Issue

I'm able to start bootloader, flash the program, jump to application, jump to bootloader and flash program again. But this is ok like 50% of the time in DEBUG. The first start and flash is always working, the first jump is almost always working and after that it depends.

In release mode, it is even worse. I can start bootloader, flash the program and most of the time I can't even jump to the application

How did I code that ?

I'm based on the renesas FSL library and working on the R5F10DPJ microcontroller. To perform the bootswapping, I'm using this function : 

void Flash_SwapBootCluster()
{
	fsl_u08 fsl_status;
	UINT32 wait;
	
	// Open FSL and prepare all functions
	FSL_Open();
	FSL_PrepareExtFunctions();

	// Invert bootflag to start correct bootloader and close FSL
	fsl_status = FSL_InvertBootFlag();
	while(fsl_status != FSL_OK)
	{
		fsl_status = FSL_InvertBootFlag();
	}

	// Close FSL
	FSL_Close();

	/* Delay */
	wait = (UINT32)0;
	while(wait < (UINT32)10000)
	{
		wait++;
	}

	// Perform swapping of bootcluster
	fsl_status = FSL_SwapBootCluster();
	while(fsl_status != FSL_OK)
	{
		fsl_status = FSL_SwapBootCluster();
	}
}

I start to be out of idea, am I doing something wrong with this boot swapping ?

Thanks in advance and have a good day !