The Riotboard User Manual doesn’t state clearly which side of the GPIO expansion port is which, so I made a diagram explaining it a bit better:
Print it out and align it with the board, and your job will be easier.
Also available in PDF form.
Month: May 2016
U-Boot fw_env.config for Riotboard
For all you U-Boot users out there, if you set bootdelay=0 on a Riotboard, you will have problems if you ever want to get back into the U-Boot configuration menu.
To erase or modify the U-Boot environment settings, you need to create an /etc/fw_env.config that the U-Boot userspace tools can use.
tl;dr
This is what the fw_env.config file should look like on a Riotboard (at least, when using a build of Freescale’s General Availability kernels):
# Device Env. Offset Env. Size Flash Sector Size /dev/mmcblk3 0x60000 0x2000 0x1000
The U-Boot environment is saved to /dev/mmcblk3, which is tricky, because the partition table explicitly defines an unused area at the beginning of the eMMC storage device.
Once you’ve got the configuration file in place, running fw_printenv should show something like:
# fw_printenv
baudrate=115200
boot_a_script=load ${devtype} ${devnum}:${bootpart} ${scriptaddr} ${prefix}${script}; source ${scriptaddr}
boot_extlinux=sysboot ${devtype} ${devnum}:${bootpart} any ${scriptaddr} ${prefix}extlinux/extlinux.conf
boot_prefixes=/ /boot/
boot_script_dhcp=boot.scr.uimg
boot_scripts=boot.scr.uimg boot.scr
boot_targets=mmc0 mmc1 mmc2 usb0 pxe dhcp
bootcmd=run distro_bootcmd
bootcmd_dhcp=usb start; if dhcp ${scriptaddr} ${boot_script_dhcp}; then source ${scriptaddr}; fi
bootcmd_mmc0=setenv devnum 0; run mmc_boot
bootcmd_mmc1=setenv devnum 1; run mmc_boot
bootcmd_mmc2=setenv devnum 2; run mmc_boot
bootcmd_pxe=usb start; dhcp; if pxe get; then pxe boot; fi
bootcmd_usb0=setenv devnum 0; run usb_boot
bootdelay=0
bootm_size=0x10000000
distro_bootcmd=for target in ${boot_targets}; do run bootcmd_${target}; done
ethact=FEC
ethprime=FEC
fdt_addr_r=0x13000000
fdtfile=imx6dl-riotboard.dtb
kernel_addr_r=0x12000000
loadaddr=0x12000000
mmc_boot=if mmc dev ${devnum}; then setenv devtype mmc; run scan_dev_for_boot_part; fi
pxefile_addr_r=0x13200000
ramdisk_addr_r=0x13300000
scan_dev_for_boot=echo Scanning ${devtype} ${devnum}:${bootpart}...; for prefix in ${boot_prefixes}; do run scan_dev_for_extlinux; run scan_dev_for_scripts; done
scan_dev_for_boot_part=part list ${devtype} ${devnum} -bootable devplist; env exists devplist || setenv devplist 1; for bootpart in ${devplist}; do if fstype ${devtype} ${devnum}:${bootpart} bootfstype; then rune
scan_dev_for_extlinux=if test -e ${devtype} ${devnum}:${bootpart} ${prefix}extlinux/extlinux.conf; then echo Found ${prefix}extlinux/extlinux.conf; run boot_extlinux; echo SCRIPT FAILED: continuing...; fi
scan_dev_for_scripts=for script in ${boot_scripts}; do if test -e ${devtype} ${devnum}:${bootpart} ${prefix}${script}; then echo Found U-Boot script ${prefix}${script}; run boot_a_script; echo SCRIPT FAILED: cone
scriptaddr=0x13100000
stderr=serial
stdin=serial
stdout=serial
usb_boot=usb start; if usb dev ${devnum}; then setenv devtype usb; run scan_dev_for_boot_part; fi
You can now use the fw_setenv command to reset the bootdelay parameter.
Figuring Out The Right Configuration Parameters
If you’re using the U-Boot riotboard_defconfig, you’ll see:
#define CONFIG_SYS_EXTRA_OPTIONS "IMX_CONFIG=board/boundary/nitrogen6x/nitrogen6s1g.cfg,MX6S,DDR_MB=1024,ENV_IS_IN_MMC"
If you then look at include/configs/embestmx6boards.h, you’ll see the configuration used to store the environment:
/* Environment organization */ #define CONFIG_ENV_SIZE (8 * 1024) #if defined(CONFIG_ENV_IS_IN_MMC) /* RiOTboard */ #define CONFIG_FDTFILE "imx6dl-riotboard.dtb" #define CONFIG_SYS_FSL_USDHC_NUM 3 #define CONFIG_SYS_MMC_ENV_DEV 2 /* SDHC4 */ #define CONFIG_ENV_OFFSET (6 * 64 * 1024) #define CONFIG_SUPPORT_EMMC_BOOT /* eMMC specific */ #elif defined(CONFIG_ENV_IS_IN_SPI_FLASH) ... #endif
Kind of a pain in the ass that no one at embest thought it would be useful to document this information.
esptool USB Serial Adapter Shootout
It’s not you, it’s the crappy counterfeit FTDI chip in your USB to serial adapter. That is what is keeping your esptool.py or esptool-ck flash download from working.
When I first started using the esp8266, I had some serious problems getting esptool.py and esptool-ck working, due to one model of super-flaky, cheap USB serial adapter not working.
This had me tearing my hair out for a few weeks, as I tried replacing everything besides the serial adapter, which I had assumed could not possibly be the culprit.
After all, USB-to-serial conversion is a solved problem, right?
Wrong.
This page is a collection of reviews of the serial adapters I’ve used, which specifically have support for the DTR / RTS signaling used to automatically reset the esp8266 and put the chip into UART firmware download mode.
Here are the adapters I’ve tried:
A – FTDI FT232RQ (4D Systems uUSB-PA5 Adapter, available here)
B – FTDI FT232RL (Chinese YP-05 counterfeit, from eBay)
C – FTDI FT232H (genuine C232HD-EDHSP-0 cable, available here)
D – Prolific PL2303HX (probably counterfeit, from eBay)
E – Silicon Labs CP2102 (black PCB, from eBay)
F – Silicon Labs CP2102 (red PCB, from eBay)
G – Silicon Labs CP2104 (blue PCB, from eBay)
H – WinChipHead CH340G (from eBay)
If there are any modules I’ve missed, or you think I should test, feel free to drop me a line with a link to where I can buy one. (Or you could send me one, I’d be happy.)
Also feel free to drop me any questions you might have about getting set up with the esp8266, I’ve got way more brain damage learning how to do this myself, so perhaps I could share some of it with you!
tl;dr
Buy either an adapter with a genuine FTDI chip, or one of the Silicon Labs CP2102 chips.
Test Results
Here are the results when testing the adapters at various baud rates with the following modules:
ESP-01 (4Mbit, 25Q41BT, blue PCB)
| Adapter | 3M | 1.5M | 921.6 | 460.8 | 230.4 | 115.2 | Log |
|---|---|---|---|---|---|---|---|
| A | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| B | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | |
| C | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| D | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | link |
| E | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| F | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| G | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| H | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | link |
ESP-01 (8Mbit, BergMicro 25Q80A, black PCB)
| Adapter | 3M | 1.5M | 921.6 | 460.8 | 230.4 | 115.2 | Log |
|---|---|---|---|---|---|---|---|
| A | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| B | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | |
| C | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| D | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ | link |
| E | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| F | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| G | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| H | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | link |
ESP-12 (32Mbit, flash_id e0 / 4016, blue PCB)
| Adapter | 3M | 1.5M | 921.6 | 460.8 | 230.4 | 115.2 | Log |
|---|---|---|---|---|---|---|---|
| A | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| B | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | link |
| C | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| D | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | link |
| E | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| F | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| G | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| H | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | link |
ESP-12E (32Mbit, flash_id e0 / 4016, black PCB)
| Adapter | 3M | 1.5M | 921.6 | 460.8 | 230.4 | 115.2 | Log |
|---|---|---|---|---|---|---|---|
| A | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| B | ✗ | ✗ | ✗ | ✗ | ✗ | ✗ | |
| C | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| D | ✓ | ✗ | ✗ | ✗ | ✗ | ✗ | link |
| E | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| F | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| G | ✗ | ✓ | ✓ | ✓ | ✓ | ✓ | link |
| H | ✗ | ✗ | ✗ | ✗ | ✗ | ✓ | link |
Pin Voltages When Idle
| Adapter | Vcc | DTR | RTS | TX | RX |
|---|---|---|---|---|---|
| A | 5.10 | 3.44 | 3.44 | 1.66 | 1.49 |
| B | 5.10 | 0.00 | 3.53 | 3.53 | 0.00 |
| C | 5.09 | 3.32 | 3.32 | 3.32 | 2.43 |
| D | 5.11 | 3.46 | 3.46 | 3.46 | 2.14 |
| E | 5.10 | 3.37 | 3.37 | 3.37 | 3.28 |
| F | 5.09 | 3.37 | 3.37 | 3.37 | 3.53 |
| G | 5.10 | 2.25 | 3.41 | 3.41 | 3.15 |
| H | 5.11 | 3.70 | 3.70 | 3.70 | 3.63 |
Test Setup
Here are the perfboards I built to program the modules:
Version 0
Only works with the 4D Systems uUSB-PA5 Adapter. Two other programming circuits on board require manual reset/mode selection and do not work.
Version 1
Version 2
Improved upon Version 1, by making a common header layout for programming: 5V (red), GND (green), DTR (yellow), RTS (blue), TX (orange), RX (gray).
The trace wires are shorter and more uniform this way, and there’s less chance of screwing up the adaptation wiring. Also, the adapters all become interchangeable, which improves test consistency.
Test Script
I’ve created a test script to test each USB adapter, using a variety of baud rates. The code is on Github here.
FTDI FT232RQ (4D Systems uUSB-PA5 Adapter)
Works.
FTDI FT232RL (Chinese counterfeit)
Does not work.
Markings on the board call it a YP-05. You can get these for about 3 EUR on eBay, and they work reasonably well as plain USB serial adapters. But they always fail for me while programming the esp8266, with the following errors:
$ ./esptool.py write_flash 0x00000 x.bin Connecting... Erasing flash... Took 2.21s to erase flash block Writing at 0x00008000... (7 %) A fatal error occurred: Invalid head of packet
and:
esptool.py v1.0.2-dev Traceback (most recent call last): File "./esptool.py", line 1213, inmain() File "./esptool.py", line 1122, in main esp = ESPROM(args.port, initial_baud) File "./esptool.py", line 70, in __init__ self._port = serial.Serial(port) File "/usr/local/lib/python2.7/dist-packages/serial/serialutil.py", line 180, in __init__ self.open() File "/usr/local/lib/python2.7/dist-packages/serial/serialposix.py", line 311, in open self._update_dtr_state() File "/usr/local/lib/python2.7/dist-packages/serial/serialposix.py", line 605, in _update_dtr_state fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_DTR_str) IOError: [Errno 5] Input/output error
The esptool programmer always stops flashing at some percentage point.
FTDI FT232H Cable (C232HD-EDHSP-0)
Works.
Prolific PL2303HX
Works, sometimes.
I honestly did not expect them to. Hilariously, these come shrink wrapped in plastic, because the USB plug support posts aren’t even soldered!
These are probably counterfeit chips, too, but who knows? Also, they don’t really work in Windows, after Prolific disabled support for counterfeit devices (though sometimes I wonder how they even know).
Thanks to Daniel for soldering the DTR and RTS wires onto the extremely thin SSOP pins. For great justice!
[30217.752502] usb 3-1.4: new full-speed USB device number 32 using ehci-pci [30217.845449] usb 3-1.4: New USB device found, idVendor=067b, idProduct=2303 [30217.845454] usb 3-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [30217.845457] usb 3-1.4: Product: USB-Serial Controller [30217.845459] usb 3-1.4: Manufacturer: Prolific Technology Inc. [30217.845884] pl2303 3-1.4:1.0: pl2303 converter detected [30217.847596] usb 3-1.4: pl2303 converter now attached to ttyUSB1
Bus 003 Device 032: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port
$ ./esptool.py read_mac esptool.py v1.0.2-dev Connecting... MAC: 5c:cf:7f:07:8e:cd $ ./esptool.py chip_id esptool.py v1.0.2-dev Connecting... Chip ID: 0x00078ecd $ ./esptool.py flash_id esptool.py v1.0.2-dev Connecting... Manufacturer: e0 Device: 4016 $ ./esptool.py read_flash 0x0 0x80000 x.bin esptool.py v1.0.2-dev Connecting... Running Cesanta flasher stub... Reading 524288 @ 0x0... 524288 (100 %) Read 524288 bytes at 0x0 in 49.9 seconds (84.0 kbit/s)... $ ./esptool.py write_flash 0x0 x.bin esptool.py v1.0.2-dev Connecting... Running Cesanta flasher stub... Flash params set to 0x0000 Writing 524288 @ 0x0... 524288 (100 %) Wrote 524288 bytes at 0x0 in 46.1 seconds (90.9 kbit/s)... Leaving...
Silicon Labs CP2102 (black PCB)
Works.
Silicon Labs CP2102 (red PCB)
Works.
[ 7727.919777] usb 2-1: new full-speed USB device number 4 using xhci_hcd [ 7728.049611] usb 2-1: New USB device found, idVendor=10c4, idProduct=ea60 [ 7728.049616] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 7728.049619] usb 2-1: Product: CP2102 USB to UART Bridge Controller [ 7728.049621] usb 2-1: Manufacturer: Silicon Labs [ 7728.049623] usb 2-1: SerialNumber: 0001 [ 7729.078772] usbcore: registered new interface driver usbserial [ 7729.078985] usbcore: registered new interface driver usbserial_generic [ 7729.079148] usbserial: USB Serial support registered for generic [ 7729.083795] usbcore: registered new interface driver cp210x [ 7729.083830] usbserial: USB Serial support registered for cp210x [ 7729.083862] cp210x 2-1:1.0: cp210x converter detected [ 7729.084803] usb 2-1: cp210x converter now attached to ttyUSB0
Bus 002 Device 007: ID 10c4:ea60 Cygnal Integrated Products, Inc. CP210x UART Bridge / myAVR mySmartUSB light
$ ./esptool.py read_flash 0x0 0x80000 x.bin esptool.py v1.0.2-dev Connecting... Running Cesanta flasher stub... Reading 524288 @ 0x0... 524288 (100 %) Read 524288 bytes at 0x0 in 60.8 seconds (69.0 kbit/s)... $ ./esptool.py write_flash 0x0 x.bin esptool.py v1.0.2-dev Connecting... Running Cesanta flasher stub... Flash params set to 0x0000 Writing 524288 @ 0x0... 524288 (100 %) Wrote 524288 bytes at 0x0 in 45.5 seconds (92.3 kbit/s)... Leaving...
Silicon Labs CP2104 (blue PCB)
Works!
After modifying the DTR line to bypass the capacitor as suggested by comments from 0xPIT, this adapter works as expected.
Doesn’t work.
Persistent errors on DTR line:
$ python esptool.py --port /dev/ttyUSB0 chip_id esptool.py v1.0.2-dev Connecting... Traceback (most recent call last): File "esptool.py", line 1214, inmain() File "esptool.py", line 1124, in main esp.connect() File "esptool.py", line 159, in connect self._port.setDTR(False) File "/usr/local/lib/python2.7/dist-packages/serial/serialutil.py", line 547, in setDTR self.dtr = value File "/usr/local/lib/python2.7/dist-packages/serial/serialutil.py", line 411, in dtr self._update_dtr_state() File "/usr/local/lib/python2.7/dist-packages/serial/serialposix.py", line 607, in _update_dtr_state fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_DTR_str) IOError: [Errno 5] Input/output error $ python esptool.py --port /dev/ttyUSB0 chip_id esptool.py v1.0.2-dev Connecting... A fatal error occurred: Failed to connect to ESP8266 $ python esptool.py --port /dev/ttyUSB0 flash_id esptool.py v1.0.2-dev Connecting... Traceback (most recent call last): File "esptool.py", line 1214, in main() File "esptool.py", line 1124, in main esp.connect() File "esptool.py", line 159, in connect self._port.setDTR(False) File "/usr/local/lib/python2.7/dist-packages/serial/serialutil.py", line 547, in setDTR self.dtr = value File "/usr/local/lib/python2.7/dist-packages/serial/serialutil.py", line 411, in dtr self._update_dtr_state() File "/usr/local/lib/python2.7/dist-packages/serial/serialposix.py", line 607, in _update_dtr_state fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_DTR_str) IOError: [Errno 5] Input/output error
[12903.595812] usb 2-1: new full-speed USB device number 12 using xhci_hcd [12903.725411] usb 2-1: New USB device found, idVendor=10c4, idProduct=ea60 [12903.725416] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [12903.725418] usb 2-1: Product: CP2104 USB to UART Bridge Controller [12903.725420] usb 2-1: Manufacturer: Silicon Labs [12903.725422] usb 2-1: SerialNumber: 0100ACEA [12903.726485] cp210x 2-1:1.0: cp210x converter detected [12903.727140] usb 2-1: cp210x converter now attached to ttyUSB0
Bus 002 Device 012: ID 10c4:ea60 Cygnal Integrated Products, Inc. CP210x UART Bridge / myAVR mySmartUSB light
WinChipHead CH340G
Works!
These things are so ridiculously cheap. They’re normally covered in a shrink-wrap plastic tube, which is because the two USB support pins aren’t even soldered!
These are more work, you have to wire the DTR / RTS lines on the SOP package.
[11337.449533] usb 2-1: new full-speed USB device number 6 using xhci_hcd [11337.578783] usb 2-1: New USB device found, idVendor=1a86, idProduct=7523 [11337.578788] usb 2-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0 [11337.578790] usb 2-1: Product: USB2.0-Serial [11338.602146] usbcore: registered new interface driver ch341 [11338.602511] usbserial: USB Serial support registered for ch341-uart [11338.602547] ch341 2-1:1.0: ch341-uart converter detected [11338.604752] usb 2-1: ch341-uart converter now attached to ttyUSB0
Bus 002 Device 006: ID 1a86:7523 QinHeng Electronics HL-340 USB-Serial adapter
$ ./esptool.py read_flash 0x0 0x80000 x.bin esptool.py v1.0.2-dev Connecting... Running Cesanta flasher stub... Reading 524288 @ 0x0... 524288 (100 %) Read 524288 bytes at 0x0 in 50.8 seconds (82.5 kbit/s)... $ ./esptool.py write_flash 0x0 x.bin esptool.py v1.0.2-dev Connecting... Running Cesanta flasher stub... Flash params set to 0x0000 Writing 524288 @ 0x0... 524288 (100 %) Wrote 524288 bytes at 0x0 in 45.5 seconds (92.3 kbit/s)... Leaving...
esptool-ck, esp8266, and FTDI Bug Hunting
Ever feel like you’re riding the Struggle Bus when using the esp8266?
tl;dr
Try a different USB serial adapter.
The Debug
This is the first part of a series on the insanely stupid amount of debugging I had to endure, in order to get started with this magnificent chip.
A lot of people seem to have problems programming it, myself included. There are a lot of documented cases of weird errors showing up, such as a flash failing at 7 or 8%, every time [1] [2] :
While I was getting up to speed on the esp8266, I built at least three programming circuits, and each one failed to upload a program correctly to the chip.
This was extremely irritating and I wasted a ridiculous amount of time trying to figure out what’s going on, whether I was at fault, or the circuit was at fault, or the uploader program was at fault.
I tried adding decoupling capacitors to the 3.3v → ground lines, I tried tying up the RESET and GPIO2 lines.
I tried the NodeMCU flasher, esptool.py, and esptool-ck, and none of them worked.
I tried on a Windows machine, on a Mac, and on a Linux machine, again nothing worked.
I tried attaching jumper cables directly between the programming pins and an FTDI serial adapter, and it still froze on upload.
I tried adding a separate 2A regulated power supply, this didn’t help either.
I even tried buying an EEPROM programming clip and seeing if I could write the EEPROM that way, no luck.
The esp8266 has become my white whale, as they say. And I will see it at the gates of Hell, waiting for me with a espcomm_send_command(FLASH_DOWNLOAD_DATA) failed message.
Or with obtuse responses like:
$ ./esptool.py --baud 115200 --port /dev/cu.usbserial-A50285BI write_flash 0x00000 nodemcu_integer_0.9.6-dev_20150704.bin Connecting... Erasing flash... Took 2.21s to erase flash block Writing at 0x00008000... (7 %) A fatal error occurred: Invalid head of packet $ ./esptool.py --baud 115200 --port /dev/cu.usbserial-A50285BI write_flash 0x00000 nodemcu_integer_0.9.6-dev_20150704.bin Connecting... Erasing flash... Took 2.32s to erase flash block Writing at 0x00005000... (4 %) A fatal error occurred: Invalid head of packet $ ./esptool.py --baud 115200 --port /dev/cu.usbserial-A50285BI write_flash 0x00000 nodemcu_integer_0.9.6-dev_20150704.bin Connecting... Erasing flash... Took 2.28s to erase flash block Writing at 0x00003c00... (3 %) A fatal error occurred: Invalid head of packet $ ./esptool.py --baud 57600 --port /dev/cu.usbserial-A50285BI write_flash 0x00000 nodemcu_integer_0.9.6-dev_20150704.bin Connecting... Erasing flash... Took 2.28s to erase flash block Writing at 0x00000000... (0 %) A fatal error occurred: Invalid head of packet $ ./esptool.py --baud 57600 --port /dev/tty.usbserial-A50285BI write_flash 0x00000 nodemcu_integer_0.9.6-dev_20150704.bin Connecting... Erasing flash... Took 2.17s to erase flash block Writing at 0x00000000... (0 %) A fatal error occurred: Invalid head of packet $ ./esptool.py --baud 230400 --port /dev/tty.usbserial-A50285BI write_flash 0x00000 nodemcu_integer_0.9.6-dev_20150704.bin Connecting... Erasing flash... Took 2.24s to erase flash block Writing at 0x00008000... (7 %) A fatal error occurred: Invalid head of packet $ ./esptool.py --baud 460800 --port /dev/tty.usbserial-A50285BI write_flash 0x00000 nodemcu_integer_0.9.6-dev_20150704.bin Connecting... Erasing flash... Took 2.25s to erase flash block Writing at 0x00008000... (7 %) A fatal error occurred: Invalid head of packet $
It was high time for me to start debugging esptool-ck, to find out why it was failing, and to see if there were problems I could solve.
I’d tried everything everything, and I was beginning to suspect my crappy, Chinese-knockoff FTDI converter is to blame. It was the one common denominator I thought could not possibly be the problem.
This gave me a good opportunity to mess around with JetBrains’ CLion, since importing esptool-ck into Xcode turned into a complete and utter clusterfuck. (Way to go, Apple. Why is Xcode such a pain in the ass to import existing files into and set dependencies? Seriously, way too hard.)
After a bit of debugging, I caught esptool-ck blocking on the tcdrain() call multiple times when running in multiple CLion lldb debugging sessions. This is interesting, and seems to be a good place to start.
I suspected that OS X might have some issues, so as a start, I modified espcomm.c to remove calls to tcdrain() under OS X. The fact that esptool-ck was unable to exit, when it got stuck in the tcdrain() pointed to a potential hardware issue with the counterfeit circuit. A genuine device should simply not exhibit problems here.
Another particularly gruesome issue with the crappy knock-off FTDI boards, was that they refused to execute the close() properly and would actually hang. So the only way to fix the situation was to unplug the counterfeit FTDI board and power cycle the esp8266.
In the end, the problem was with the counterfeit FTDI hardware. Don’t buy this adapter for esp8266 programming, you will totally regret it:
After testing out an adapter using a genuine FTDI chip, all of the programming methods worked just fine.