What i did / Steps to reproduce

Open the map on firefox, (on chrome there isn't this problem)

Expected result

See both the hires and the lowres layer

Actual result

Being able to see only the hires layer

Context

BlueMap Version:
3.14-spigot-1.20.1

Client: Debian buster ARM, Firefox 102.12.0esr (64 bit),
Server: Debian buster ARM, Paper 1.20.1-32.jar

It worked thanks :)

Firefox works fine for me.
Can you please check if there is an error in your browser-console and provide it?

I found something
THREE.WebGLProgram: Shader Error 0 - VALIDATE_STATUS false

Program Info Log: Must have a compiled vertex shader attached:
SHADER_INFO_LOG:
ERROR: 0:162: 'texture' : no matching overloaded function found
ERROR: 0:162: '=' : dimension mismatch
ERROR: 0:162: '=' : cannot convert from 'const mediump float' to 'highp 4-component vector of float'
VERTEX

ERROR: 0:162: 'texture' : no matching overloaded function found
ERROR: 0:162: '=' : dimension mismatch
ERROR: 0:162: '=' : cannot convert from 'const mediump float' to 'highp 4-component vector of float'

157: }
158:
159: void main() {
160: vPosition = position;
161:

162: vec4 meta = texture(textureImage, posToMetaUV(position.xz));
163: vPosition.y = metaToHeight(meta) + 1.0 - position.x * 0.0001 - position.z * 0.0002; //including small offset-tilt to prevent z-fighting
164:
165: vec4 worldPos = modelMatrix * vec4(vPosition, 1);
166: vec4 viewPos = viewMatrix * worldPos;
167:
168: vWorldPosition = worldPos.xyz;
0:1(12): warning: extension GL_ARB_gpu_shader5' unsupported in fragment shader 0:2(12): warning: extension GL_EXT_gpu_shader5' unsupported in fragment shader

Make sure you have Hardware-Acceleration enabled on Firefox :)