But as you seem to have it for some time, probably something else.
What board do you select??
Firmware problem Well, as I understand that shield indeed has some firmware in it already but usually that is overwritten when you upload something, so' firmware' is never the problem
What I am wondering... your shield supposedly works as an AP in default mode. Is it indeed working as such?
Also.. are you sure you are even supposed to upload programs? As I understand it works either as AP or as an Arduino shield, I didnt get the impression you are supposed to program it yourself, but apparently you can if you use the 'key' pin. You have checked the manual right? https://fineshang.gitbooks.io/esp8266-b ... pter4.html.
To use it as a 'standalone development board; banggood advises to load the 'AT-firmware' or 'NodeMCU' which would indicate that one can upload software. But since you specifically bought this (rather expensive one) i presume you want to keep the AP node software in it. Do realize you lose that even if you upload the tiniest program.
Also.. how are you uploading, from your posting at the link you gave I understood you are using ESPtool? But also the IDE am I correct?
Also you refer to it as an "Arduino shield" so where to are you actually uploading your programs? to the Arduino or to this board? as I dont see any USB on this board, I presume you are uploading to the Arduino?
I presume that as the communication between Arduino and this board in AT mode is via the serial port. so if you have the board on top of the Arduino.... you cannot use the serial port for uploading.
So if indeed you are uploading to the USB of the Arduino and you have this board connected, remove the board and then upload to your arduino and stick the board back in. The program you were trying to upload is apparently for the Wemos... that will most likely not work on an Arduino + WiFi shield that is controlled by AT commands