diff --git a/wgpu-hal/src/auxil/dxgi/conv.rs b/wgpu-hal/src/auxil/dxgi/conv.rs
index 384775c3e..faf42bc98 100644
--- a/wgpu-hal/src/auxil/dxgi/conv.rs
+++ b/wgpu-hal/src/auxil/dxgi/conv.rs
@@ -1,10 +1,10 @@
 use winapi::shared::dxgiformat;
 
-pub fn map_texture_format(format: wgt::TextureFormat) -> dxgiformat::DXGI_FORMAT {
+pub fn map_texture_format_failable(format: wgt::TextureFormat) -> Option<dxgiformat::DXGI_FORMAT> {
     use wgt::TextureFormat as Tf;
     use winapi::shared::dxgiformat::*;
 
-    match format {
+    Some(match format {
         Tf::R8Unorm => DXGI_FORMAT_R8_UNORM,
         Tf::R8Snorm => DXGI_FORMAT_R8_SNORM,
         Tf::R8Uint => DXGI_FORMAT_R8_UINT,
@@ -78,7 +78,14 @@ pub fn map_texture_format(format: wgt::TextureFormat) -> dxgiformat::DXGI_FORMAT
         | Tf::Astc {
             block: _,
             channel: _,
-        } => unreachable!(),
+        } => return None,
+    })
+}
+
+pub fn map_texture_format(format: wgt::TextureFormat) -> dxgiformat::DXGI_FORMAT {
+    match map_texture_format_failable(format) {
+        Some(f) => f,
+        None => unreachable!(),
     }
 }
 
diff --git a/wgpu-hal/src/dx12/adapter.rs b/wgpu-hal/src/dx12/adapter.rs
index 0bf3423f9..091a87105 100644
--- a/wgpu-hal/src/dx12/adapter.rs
+++ b/wgpu-hal/src/dx12/adapter.rs
@@ -336,7 +336,10 @@ impl crate::Adapter<super::Api> for super::Adapter {
     ) -> crate::TextureFormatCapabilities {
         use crate::TextureFormatCapabilities as Tfc;
 
-        let raw_format = auxil::dxgi::conv::map_texture_format(format);
+        let raw_format = match auxil::dxgi::conv::map_texture_format_failable(format) {
+            Some(f) => f,
+            None => return Tfc::empty(),
+        };
         let mut data = d3d12::D3D12_FEATURE_DATA_FORMAT_SUPPORT {
             Format: raw_format,
             Support1: mem::zeroed(),
diff --git a/wgpu-hal/src/vulkan/adapter.rs b/wgpu-hal/src/vulkan/adapter.rs
index 4bfe3fd81..735f6ca36 100644
--- a/wgpu-hal/src/vulkan/adapter.rs
+++ b/wgpu-hal/src/vulkan/adapter.rs
@@ -1459,8 +1459,11 @@ impl crate::Adapter<super::Api> for super::Adapter {
         let properties = self
             .phd_capabilities
             .formats
-            .get(vk_format.as_raw() as usize)
-            .unwrap();
+            .get(vk_format.as_raw() as usize);
+        let properties = match properties {
+            Some(p) => p,
+            None => return Tfc::empty(),
+        };
         let features = properties.optimal_tiling_features;
 
         let mut flags = Tfc::empty();