Pico and ESP8266

I'm trying to make Olimex's ESP8266 board (MOD-WIFI-ESP8266 Rev. A) work with the Pico. I'm using the 10 uF capacitor. I don't have a shim (and it doesn't fit Olimex's board anyways).

The firmware version test revealed "AT+GMR\r\r\n00160901\r\n\r\nOK\r\n" at 115200 Bd, so the firmware version seems to be 00160901. I hoped it would work out of the box, but it doesn't. The example crashes with the following error message:

>Uncaught ATE0 failed: no this fun
 at line 2 col 18

No this fun indeed. I figured that the best bet would be to update the firmware to one tested with Espruino, so I downloaded version 0.50.0.0.

With regards to the module documentation:

• Where it says "Connect to Espruino, copy and paste this code into the left-hand side, and disconnect" you might want to add that "disconnect" means to disconnect the WebIDE (and not disconnect the Pico from USB or the ESP from Pico)
  
• You might also want to add that Mac users first need to install pySerial as described here because otherwise the esptool will just crash with a cryptic error message
  
  

In order to put the the ESP into boot mode on the Olimex board, I actually had to solder: the GPIO0 solder jumper needs to be put into position 0 (more about this).

I successfully flashed the new firmware, soldered the jumper back to 1 and... nothing. Now the board doesn't respond anymore, also the firmware check program just returns 3 empty strings :(

What did I do wrong?

And what was I supposed to flash to where? The firmware zip files comes with many bin files, but the included readme is not clear. I flashed the boot_v1.4(b1).bin file to address 0 and the user1.2048.new.5.bin file to address 0x1000 - is that wrong?