You can buy h/w to RS232c old serial to all ARM mcu’s
They have a Loader that first listens on Old serial , then
on SPI bus . This makes ARM 7,9 the easiest mcu to boot .
But i see nothing here about how to “work” with WXP and
device mangler , to set up the driver . I remember doin it
years ago , but didnt note it .
Next step is to attach LEDs to ports and repeatedly
load your 500 bytes and crash , then
reset load reset til it lights a LED .
There is no faster way to test H/W .
This is what ST would do to test its pdt .