diff --git a/flake.nix b/flake.nix
index 787d704..4946d9c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -65,10 +65,7 @@
           # Inherit inputs from checks.
           checks = self.checks.${system};
 
-          # Additional dev-shell environment variables can be set directly
-          # MY_CUSTOM_DEVELOPMENT_VAR = "something else";
-
-          # Extra inputs can be added here; cargo and rustc are provided by default.
+          RUST_LOG = "debug";
           packages = [
             # pkgs.ripgrep
           ];
diff --git a/src/config.rs b/src/config.rs
index 25491f4..57ce7be 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,6 +1,5 @@
 use serde::{Deserialize, Serialize};
 use toml::Table;
-use toml::map::Map;
 
 #[derive(Serialize, Deserialize)]
 pub struct Config {
diff --git a/src/cpu.rs b/src/cpu.rs
index 3952fbb..b1a313d 100644
--- a/src/cpu.rs
+++ b/src/cpu.rs
@@ -22,12 +22,25 @@ pub struct CpuCore {
 }
 
 #[derive(Debug, Clone, Copy)]
-enum CoreType {
+pub enum CoreType {
     P, // Performence
     E, // Efficent
     L, // Low power
 }
 
+impl TryFrom<String> for CoreType {
+    type Error = &'static str;
+
+    fn try_from(value: String) -> Result<Self, Self::Error> {
+        match value.as_str() {
+            "E" => Ok(CoreType::E),
+            "P" => Ok(CoreType::P),
+            "L" => Ok(CoreType::L),
+            _ => Err(""),
+        }
+    }
+}
+
 impl CpuCore {
     fn determine_core_type() -> Result<CoreType, ()> {
         if !(CpuCore::is_atomic()?) {
diff --git a/src/main.rs b/src/main.rs
index d4769db..4057763 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,11 +1,11 @@
 use clap::Parser;
 use raw_cpuid::*;
 use std::path::PathBuf;
-use tracing::{debug, info, warn};
+use tracing::{debug, error, info, warn};
 
 use crate::{
     config::Config,
-    cpu::{Cpu, CpuCore},
+    cpu::{CoreType, Cpu, CpuCore},
 };
 mod config;
 mod cpu;
@@ -19,40 +19,45 @@ struct Args {
 }
 
 fn main() {
+    tracing_subscriber::fmt::init();
     let args = Args::parse();
+    let mut custom_cpu: Option<Cpu> = None;
 
     if let Some(config) = args.config {
         let config_buf = std::fs::read(config).unwrap();
         let config_par: Config = toml::from_slice(&config_buf).unwrap();
         if let Some(comp) = config_par.cpu.comp {
             warn!("Using custom cpu topo loaded from config!");
-            let custom_topo: Vec<CpuCore> = Vec::new();
+            let mut custom_topo: Vec<CpuCore> = Vec::new();
             for x in comp {
                 custom_topo.push(CpuCore {
                     id: x.0.parse().unwrap(),
                     core_type: {
                         match x.1 {
-                            toml::Value::String(y) => match y.as_str() {
-                                "P" => {}
-                                "E" => {}
-                                "L" => {}
-                                _ => {
-                                    unreachable!()
+                            toml::Value::String(y) => {
+                                if let Ok(ParsedCoreType) = CoreType::try_from(y.clone()) {
+                                    ParsedCoreType
+                                } else {
+                                    error!("Couldn't parse {:?} as CoreType", y);
+                                    unreachable!("");
                                 }
-                            },
+                            }
                             _ => {
-                                unreachable!()
+                                unreachable!("")
                             }
                         }
                     },
                 })
             }
+            custom_cpu = Some(Cpu { cores: custom_topo });
         }
-        Cpu { cores: vec![] };
     }
 
-    tracing_subscriber::fmt::init();
-
-    let cpu = cpu::Cpu::new();
+    let mut cpu: Cpu;
+    if custom_cpu.is_none() {
+        cpu = cpu::Cpu::new();
+    } else {
+        cpu = custom_cpu.unwrap();
+    };
     debug!("{cpu:?}");
 }
diff --git a/test_config.toml b/test_config.toml
index 490af3b..57c179b 100644
--- a/test_config.toml
+++ b/test_config.toml
@@ -1,4 +1,4 @@
 [cpu]
 comp = {
-"0" = {type = E}
+"0" = "E"
 }