Item 1: When running "make flash" I see the following warning: Running make flash... /Users/casner/src/github/esp-idf/components/partition_table/Makefile.projbuild:16: warning: undefined variable `MD5_OPT' Flashing binaries to serial port /dev/cu.SLAB_USBtoUART (app at offset 0x10000)... A grep for MD5_OPT in the esp-idf source tree only finds the two instances in Makefile.projbuild, so it looks like is not defined anywhere if CONFIG_PARTITION_TABLE_MD5=y. Do others see this warning? If not, I must need to update something. Item 2: I don't have an SD card installed, but I see the following errors at boot time (with current Master sources): I (2492) sdcard: SD CARD has been inserted E (2532) sdmmc_req: handle_idle_state_events unhandled: 00000004 00000000 E (2532) sdmmc_cmd: sdmmc_card_init: send_op_cond (1) returned 0x107 -- Steve