diff --git a/crates/keyfork-shard/src/lib.rs b/crates/keyfork-shard/src/lib.rs
index b98de30..01e01d1 100644
--- a/crates/keyfork-shard/src/lib.rs
+++ b/crates/keyfork-shard/src/lib.rs
@@ -130,7 +130,7 @@ pub fn remote_decrypt(w: &mut impl Write) -> Result<(), Box<dyn std::error::Erro
                 };
 
                 let [pubkey_mnemonic, payload_mnemonic] = pm
-                    .prompt_validated_wordlist::<English, _, _, _>(
+                    .prompt_validated_wordlist::<English, _>(
                         QRCODE_COULDNT_READ,
                         3,
                         validator.to_fn(),
diff --git a/crates/keyfork-shard/src/openpgp.rs b/crates/keyfork-shard/src/openpgp.rs
index c364d50..1135265 100644
--- a/crates/keyfork-shard/src/openpgp.rs
+++ b/crates/keyfork-shard/src/openpgp.rs
@@ -495,7 +495,7 @@ pub fn decrypt(
             let validator = MnemonicSetValidator {
                 word_lengths: [9, 24],
             };
-            let [nonce_mnemonic, pubkey_mnemonic] = pm.prompt_validated_wordlist::<English, _, _, _>(
+            let [nonce_mnemonic, pubkey_mnemonic] = pm.prompt_validated_wordlist::<English, _>(
                 QRCODE_COULDNT_READ,
                 3,
                 validator.to_fn(),
diff --git a/crates/keyfork/src/cli/recover.rs b/crates/keyfork/src/cli/recover.rs
index 41184ee..d68a193 100644
--- a/crates/keyfork/src/cli/recover.rs
+++ b/crates/keyfork/src/cli/recover.rs
@@ -69,7 +69,7 @@ impl RecoverSubcommands {
                 let validator = MnemonicChoiceValidator {
                     word_lengths: [WordLength::Count(12), WordLength::Count(24)],
                 };
-                let mnemonic = term.prompt_validated_wordlist::<English, _, _, _>(
+                let mnemonic = term.prompt_validated_wordlist::<English, _>(
                     "Mnemonic: ",
                     3,
                     validator.to_fn(),
diff --git a/crates/util/keyfork-prompt/examples/test-basic-prompt.rs b/crates/util/keyfork-prompt/examples/test-basic-prompt.rs
index c1f4302..04c7391 100644
--- a/crates/util/keyfork-prompt/examples/test-basic-prompt.rs
+++ b/crates/util/keyfork-prompt/examples/test-basic-prompt.rs
@@ -18,7 +18,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
         word_lengths: [24, 48],
     };
 
-    let mnemonics = mgr.prompt_validated_wordlist::<English, _, _, _>(
+    let mnemonics = mgr.prompt_validated_wordlist::<English, _>(
         "Enter a 9-word and 24-word mnemonic: ",
         3,
         transport_validator.to_fn(),
@@ -26,7 +26,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     assert_eq!(mnemonics[0].as_bytes().len(), 12);
     assert_eq!(mnemonics[1].as_bytes().len(), 32);
 
-    let mnemonics = mgr.prompt_validated_wordlist::<English, _, _, _>(
+    let mnemonics = mgr.prompt_validated_wordlist::<English, _>(
         "Enter a 24 and 48-word mnemonic: ",
         3,
         combine_validator.to_fn(),
diff --git a/crates/util/keyfork-prompt/src/lib.rs b/crates/util/keyfork-prompt/src/lib.rs
index 9c73e8a..e12597b 100644
--- a/crates/util/keyfork-prompt/src/lib.rs
+++ b/crates/util/keyfork-prompt/src/lib.rs
@@ -68,15 +68,13 @@ pub trait PromptHandler {
     /// The method may return an error if the message was not able to be displayed, if the input
     /// could not be read, or if the parser returned an error.
     #[cfg(feature = "mnemonic")]
-    fn prompt_validated_wordlist<X, V, F, E>(
+    fn prompt_validated_wordlist<X, V>(
         &mut self,
         prompt: &str,
         retries: u8,
-        validator_fn: F,
+        validator_fn: impl Fn(String) -> Result<V, Box<dyn std::error::Error>>,
     ) -> Result<V, Error>
     where
-        F: Fn(String) -> Result<V, E>,
-        E: std::error::Error,
         X: Wordlist;
 
     /// Prompt the user for a passphrase, which is hidden while typing.
@@ -92,15 +90,12 @@ pub trait PromptHandler {
     /// # Errors
     /// The method may return an error if the message was not able to be displayed, if the input
     /// could not be read, or if the parser returned an error.
-    fn prompt_validated_passphrase<V, F, E>(
+    fn prompt_validated_passphrase<V>(
         &mut self,
         prompt: &str,
         retries: u8,
-        validator_fn: F,
-    ) -> Result<V, Error>
-    where
-        F: Fn(String) -> Result<V, E>,
-        E: std::error::Error;
+        validator_fn: impl Fn(String) -> Result<V, Box<dyn std::error::Error>>,
+    ) -> Result<V, Error>;
 
     /// Prompt the user with a [`Message`].
     ///
diff --git a/crates/util/keyfork-prompt/src/terminal.rs b/crates/util/keyfork-prompt/src/terminal.rs
index 64eb8be..0b5e6bd 100644
--- a/crates/util/keyfork-prompt/src/terminal.rs
+++ b/crates/util/keyfork-prompt/src/terminal.rs
@@ -1,6 +1,7 @@
 use std::{
+    borrow::Borrow,
     io::{stderr, stdin, BufRead, BufReader, Read, Stderr, Stdin, Write},
-    os::fd::AsRawFd, borrow::Borrow,
+    os::fd::AsRawFd,
 };
 
 use keyfork_crossterm::{
@@ -12,7 +13,7 @@ use keyfork_crossterm::{
     ExecutableCommand, QueueableCommand,
 };
 
-use crate::{PromptHandler, Message, Wordlist, Error};
+use crate::{Error, Message, PromptHandler, Wordlist};
 
 #[allow(missing_docs)]
 pub type Result<T, E = Error> = std::result::Result<T, E>;
@@ -155,11 +156,13 @@ where
     fn lock(&mut self) -> TerminalGuard<'_, R, W> {
         TerminalGuard::new(&mut self.read, &mut self.write, &mut self.terminal)
     }
-
 }
 
-impl<R, W> PromptHandler for Terminal<R, W> where R: Read + Sized, W: Write + AsRawFd + Sized {
-
+impl<R, W> PromptHandler for Terminal<R, W>
+where
+    R: Read + Sized,
+    W: Write + AsRawFd + Sized,
+{
     fn prompt_input(&mut self, prompt: &str) -> Result<String> {
         let mut terminal = self.lock().alternate_screen()?;
         terminal
@@ -182,15 +185,13 @@ impl<R, W> PromptHandler for Terminal<R, W> where R: Read + Sized, W: Write + As
     }
 
     #[cfg(feature = "mnemonic")]
-    fn prompt_validated_wordlist<X, V, F, E>(
+    fn prompt_validated_wordlist<X, V>(
         &mut self,
         prompt: &str,
         retries: u8,
-        validator_fn: F,
+        validator_fn: impl Fn(String) -> Result<V, Box<dyn std::error::Error>>,
     ) -> Result<V, Error>
     where
-        F: Fn(String) -> Result<V, E>,
-        E: std::error::Error,
         X: Wordlist,
     {
         let mut last_error = None;
@@ -214,7 +215,10 @@ impl<R, W> PromptHandler for Terminal<R, W> where R: Read + Sized, W: Write + As
 
     #[cfg(feature = "mnemonic")]
     #[allow(clippy::too_many_lines)]
-    fn prompt_wordlist<X>(&mut self, prompt: &str) -> Result<String> where X: Wordlist {
+    fn prompt_wordlist<X>(&mut self, prompt: &str) -> Result<String>
+    where
+        X: Wordlist,
+    {
         let wordlist = X::get_singleton();
         let words = wordlist.to_str_array();
 
@@ -340,16 +344,12 @@ impl<R, W> PromptHandler for Terminal<R, W> where R: Read + Sized, W: Write + As
         Ok(input)
     }
 
-    fn prompt_validated_passphrase<V, F, E>(
+    fn prompt_validated_passphrase<V>(
         &mut self,
         prompt: &str,
         retries: u8,
-        validator_fn: F,
-    ) -> Result<V, Error>
-    where
-        F: Fn(String) -> Result<V, E>,
-        E: std::error::Error,
-    {
+        validator_fn: impl Fn(String) -> Result<V, Box<dyn std::error::Error>>,
+    ) -> Result<V, Error> {
         let mut last_error = None;
         for _ in 0..retries {
             let s = self.prompt_passphrase(prompt)?;
diff --git a/crates/util/keyfork-prompt/src/validators.rs b/crates/util/keyfork-prompt/src/validators.rs
index e05e21f..8d10dcf 100644
--- a/crates/util/keyfork-prompt/src/validators.rs
+++ b/crates/util/keyfork-prompt/src/validators.rs
@@ -12,7 +12,7 @@ pub trait Validator {
     type Error;
 
     /// Create a validator function from the given parameters.
-    fn to_fn(&self) -> Box<dyn Fn(String) -> Result<Self::Output, Self::Error>>;
+    fn to_fn(&self) -> Box<dyn Fn(String) -> Result<Self::Output, Box<dyn std::error::Error>>>;
 }
 
 /// A PIN could not be validated from the given input.
@@ -48,7 +48,7 @@ impl Validator for PinValidator {
     type Output = String;
     type Error = PinError;
 
-    fn to_fn(&self) -> Box<dyn Fn(String) -> Result<String, PinError>> {
+    fn to_fn(&self) -> Box<dyn Fn(String) -> Result<String, Box<dyn std::error::Error>>> {
         let min_len = self.min_length.unwrap_or(usize::MIN);
         let max_len = self.max_length.unwrap_or(usize::MAX);
         let range = self.range.clone().unwrap_or('0'..='9');
@@ -56,14 +56,14 @@ impl Validator for PinValidator {
             s.truncate(s.trim_end().len());
             let len = s.len();
             if len < min_len {
-                return Err(PinError::TooShort(len, min_len));
+                return Err(Box::new(PinError::TooShort(len, min_len)));
             }
             if len > max_len {
-                return Err(PinError::TooLong(len, max_len));
+                return Err(Box::new(PinError::TooLong(len, max_len)));
             }
             for (index, ch) in s.chars().enumerate() {
                 if !range.contains(&ch) {
-                    return Err(PinError::InvalidCharacters(ch, index));
+                    return Err(Box::new(PinError::InvalidCharacters(ch, index)));
                 }
             }
             Ok(s)
@@ -123,13 +123,13 @@ pub mod mnemonic {
         type Output = Mnemonic;
         type Error = MnemonicValidationError;
 
-        fn to_fn(&self) -> Box<dyn Fn(String) -> Result<Mnemonic, Self::Error>> {
+        fn to_fn(&self) -> Box<dyn Fn(String) -> Result<Mnemonic, Box<dyn std::error::Error>>> {
             let word_length = self.word_length.clone();
             Box::new(move |s: String| match word_length.as_ref() {
                 Some(wl) => {
                     let count = s.split_whitespace().count();
                     if !wl.matches(count) {
-                        return Err(Self::Error::InvalidLength(count, wl.clone()));
+                        return Err(Box::new(Self::Error::InvalidLength(count, wl.clone())));
                     }
                     let m = Mnemonic::from_str(&s)?;
                     Ok(m)
@@ -165,7 +165,7 @@ pub mod mnemonic {
         type Output = Mnemonic;
         type Error = MnemonicChoiceValidationError;
 
-        fn to_fn(&self) -> Box<dyn Fn(String) -> Result<Self::Output, Self::Error>> {
+        fn to_fn(&self) -> Box<dyn Fn(String) -> Result<Self::Output, Box<dyn std::error::Error>>> {
             let word_lengths = self.word_lengths.clone();
             Box::new(move |s: String| {
                 let count = s.split_whitespace().count();
@@ -175,10 +175,10 @@ pub mod mnemonic {
                         return Ok(m);
                     }
                 }
-                Err(MnemonicChoiceValidationError::InvalidLength(
+                Err(Box::new(MnemonicChoiceValidationError::InvalidLength(
                     count,
                     word_lengths.to_vec(),
-                ))
+                )))
             })
         }
     }
@@ -207,7 +207,7 @@ pub mod mnemonic {
         type Output = [Mnemonic; N];
         type Error = MnemonicSetValidationError;
 
-        fn to_fn(&self) -> Box<dyn Fn(String) -> Result<Self::Output, Self::Error>> {
+        fn to_fn(&self) -> Box<dyn Fn(String) -> Result<Self::Output, Box<dyn std::error::Error>>> {
             let word_lengths = self.word_lengths;
             Box::new(move |s: String| {
                 let mut counter: usize = 0;
@@ -219,15 +219,17 @@ pub mod mnemonic {
                         .take(word_length)
                         .collect::<Vec<_>>();
                     if words.len() != word_length {
-                        return Err(MnemonicSetValidationError::InvalidSetLength(
+                        return Err(Box::new(MnemonicSetValidationError::InvalidSetLength(
                             word_set,
                             words.len(),
                             word_length,
-                        ));
+                        )));
                     }
                     let mnemonic = match Mnemonic::from_str(&words.join(" ")) {
                         Ok(m) => m,
-                        Err(e) => return Err(Self::Error::MnemonicFromStrError(word_set, e)),
+                        Err(e) => {
+                            return Err(Box::new(Self::Error::MnemonicFromStrError(word_set, e)))
+                        }
                     };
                     output.push(mnemonic);
                     counter += word_length;