flash read err, 1000

[espiot]

For one of the ESP32_Devkitc_v4 board, make erase_flash then make flash monitor unable to boot it up (show below).

But if I briefly short GPIO12 to 3V3, /dev/cu.SLAB_USBtoUART would be disconnect and red LED dimmed, this time press En button would boot normally. If I short GPIO12 for too long. The /dev/cu.SLAB_USBtoUART will disappear. Reconnect the cable and press En this time will boot with 'flash read err, 1000' but continues anyway (see further below ----).

What's the reason behind? Thanks.

esptool.py v2.1
Flashing binaries to serial port /dev/cu.SLAB_USBtoUART (app at offset 0x10000)...
esptool.py v2.1
Connecting........_
Chip is ESP32D0WDQ6 (revision 1)
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 921600
Changed.
Configuring flash size...
Auto-detected Flash size: 4MB
Flash params set to 0x0220
Compressed 19408 bytes to 11442...
Wrote 19408 bytes (11442 compressed) at 0x00001000 in 0.1 seconds (effective 1153.2 kbit/s)...
Hash of data verified.
Compressed 551680 bytes to 350076...
Wrote 551680 bytes (350076 compressed) at 0x00010000 in 5.3 seconds (effective 830.7 kbit/s)...
Hash of data verified.
Compressed 3072 bytes to 82...
Wrote 3072 bytes (82 compressed) at 0x00008000 in 0.0 seconds (effective 4501.1 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting...
MONITOR
--- idf_monitor on /dev/cu.SLAB_USBtoUART 115200 ---
--- Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H ---







-----------------------------

ets Jun 8 2016 00:22:57

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
flash read err, 1000
ets_main.c 371
ets Jun 8 2016 00:22:57

rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:5552
ho 0 tail 12 room 4
load:0x40078000,len:0
load:0x40078000,len:13756
entry 0x40078fb4
I (30) boot: ESP-IDF v3.0.1 2nd stage bootloader
I (30) boot: compile time 09:45:38
I (30) boot: Enabling RNG early entropy source...
I (35) boot: SPI Speed : 40MHz
I (39) boot: SPI Mode : DIO
I (43) boot: SPI Flash Size : 4MB
I (47) boot: Partition Table:
I (51) boot: ## Label Usage Type ST Offset Length
I (58) boot: 0 nvs WiFi data 01 02 00009000 00006000
I (65) boot: 1 phy_init RF data 01 01 0000f000 00001000
I (73) boot: 2 factory factory app 00 00 00010000 00100000
I (80) boot: End of partition table
I (84) esp_image: segment 0: paddr=0x00010020 vaddr=0x3f400020 size=0x1cdc0 (118208) map
I (135) esp_image: segment 1: paddr=0x0002cde8 vaddr=0x3ffb0000 size=0x03214 ( 12820) load
I (140) esp_image: segment 2: paddr=0x00030004 vaddr=0x40080000 size=0x0000c ( 12) load
I (142) esp_image: segment 3: paddr=0x00030018 vaddr=0x400d0018 size=0x5b728 (374568) map
I (282) esp_image: segment 4: paddr=0x0008b748 vaddr=0x4008000c size=0x003f4 ( 1012) load
I (282) esp_image: segment 5: paddr=0x0008bb44 vaddr=0x40080400 size=0x0af8c ( 44940) load
I (307) esp_image: segment 6: paddr=0x00096ad8 vaddr=0x400c0000 size=0x00000 ( 0) load
I (314) boot: Loaded app from partition at offset 0x10000
I (314) boot: Disabling RNG early entropy source...
I (316) cpu_start: Pro cpu up.
I (320) cpu_start: Starting app cpu, entry point is 0x40080fcc
I (0) cpu_start: App cpu up.
I (331) heap_init: Initializing. RAM available for dynamic allocation:
I (337) heap_init: At 3FFAE6E0 len 00001920 (6 KiB): DRAM
I (343) heap_init: At 3FFB8FA8 len 00027058 (156 KiB): DRAM
I (350) heap_init: At 3FFE0440 len 00003BC0 (14 KiB): D/IRAM
I (356) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM
I (362) heap_init: At 4008B38C len 00014C74 (83 KiB): IRAM
I (369) cpu_start: Pro cpu start user code
I (51) pm_esp32: Frequency switching config: CPU_MAX: 160, APB_MAX: 80, APB_MIN: XTAL, Light sleep: DISABLED
I (52) cpu_start: Starting scheduler on PRO CPU.
I (0) cpu_start: Starting scheduler on APP CPU.

[ESP_Sprite]

GPIO12 is a bootstrap pin, the value read on power-up will set the flash working voltage. You may be running into something related to that.