The SPI panda boot loop called recover_internal_panda() whenever the panda
did not appear within 20s after a reset. recover() erases both the bootstub
and app sectors (dfu.py program_bootstub erases sectors 0+1) before
reflashing, so a working panda that booted slowly lost its app firmware.
Fix:
- pandad.py: wait up to 60s for the panda, retry the normal reset 3x, and
only enter the ROM bootloader (recover) when the panda is confirmed in DFU
or all normal resets failed - preserving provisioning of blank boards.
- hardware.py: align recover_internal_panda() timing with the working manual
flash scripts (0.2s reset hold, 1s settle, keep BOOT0 high).
- spi.py: raise the SPI bootloader ack timeout from 0.01s to 0.1s so the DFU
flash reliably succeeds instead of erasing then failing.