GLSL read+write image2D

1) It is an Amazon Fire HD 8" (6th Gen)
2) Minimal repro and notes below

#version 310 es
precision highp image2D;
layout(rgba32f, binding=0) uniform image2D x;
layout(local_size_x=8, local_size_y=8) in;
void main () {
   ivec2 i = ivec2(gl_GlobalInvocationID.xy);
   imageStore(x, i, imageLoad(x, i));
}

Shader error:
0:3: S0001: Image has to be qualified as 'readonly', 'writeonly' or both.

After my initial post I found I could work around the error by declaring the image2D twice. Once as readonly, then again as writeonly and both using the same binding number. So that is what I'm doing now to work around things on the shaders where this is triggering.  

1) It is an Amazon Fire HD 8" (6th Gen)
2) Minimal repro and notes below

#version 310 es
precision highp image2D;
layout(rgba32f, binding=0) uniform image2D x;
layout(local_size_x=8, local_size_y=8) in;
void main () {
   ivec2 i = ivec2(gl_GlobalInvocationID.xy);
   imageStore(x, i, imageLoad(x, i));
}

Shader error:
0:3: S0001: Image has to be qualified as 'readonly', 'writeonly' or both.

After my initial post I found I could work around the error by declaring the image2D twice. Once as readonly, then again as writeonly and both using the same binding number. So that is what I'm doing now to work around things on the shaders where this is triggering.