5eb9f9d060
Commit efbf08266b6 moved _estack in order to ensure 8-byte alignment of the stack, but the address of _bootloader_dbl_tap must remain right at the end of SRAM. I verified by reading the source that the 4-byte-aligned address is used for all samd21 / samd51 boards in adafruit/circuitpython@efbf08266b. However, I only tested on trinket_m0. Closes: #739