Eliminates accessing array out of it's bounds - below array first element in next line, where buffer[bufferIndex-13] is used. When bufferIndex would be less than 12, out of bounds memory access would occur.
STM32F429/439 are Cortex M4 processors.
By comparing this file with the appropriate startup_stm32f429bitx.s file generated by the current STM32CubeIDE for STM32F429BI (as in TX16S, T16 & T18) , I can see that the present OpenTX version misses an initial stack pointer setting.
Both issues fixed herewith.
Main task size currently in double words, the CoOS RTOS task stack sizes in bytes.
Available stack size output was in double words, now everything uniform in bytes also added "bytes" label to CLI output to make this clear.
