diff --git a/binaries/cuprated/Cargo.toml b/binaries/cuprated/Cargo.toml
index 9f7a699b..e1d0573b 100644
--- a/binaries/cuprated/Cargo.toml
+++ b/binaries/cuprated/Cargo.toml
@@ -34,7 +34,7 @@ cuprate-test-utils        = { workspace = true }
 cuprate-types             = { workspace = true, features = ["json"] }
 cuprate-json-rpc          = { workspace = true }
 cuprate-rpc-interface     = { workspace = true }
-cuprate-rpc-types         = { workspace = true }
+cuprate-rpc-types         = { workspace = true, features = ["from"] }
 
 
 # TODO: after v1.0.0, remove unneeded dependencies.
diff --git a/binaries/cuprated/src/rpc/helper.rs b/binaries/cuprated/src/rpc/helper.rs
index cf5bbc49..98305dfa 100644
--- a/binaries/cuprated/src/rpc/helper.rs
+++ b/binaries/cuprated/src/rpc/helper.rs
@@ -57,17 +57,17 @@ pub(super) async fn block_header(
         )
         .await?;
 
-        let pow_hash = blockchain_context::calculate_pow(
-            &mut state.blockchain_context,
-            hardfork,
-            block,
-            seed_hash,
+        Some(
+            blockchain_context::calculate_pow(
+                &mut state.blockchain_context,
+                hardfork,
+                block,
+                seed_hash,
+            )
+            .await?,
         )
-        .await?;
-
-        pow_hash
     } else {
-        [0; 32]
+        None
     };
 
     let block_weight = usize_to_u64(header.block_weight);
diff --git a/binaries/cuprated/src/rpc/json.rs b/binaries/cuprated/src/rpc/json.rs
index 7ee16387..998d3519 100644
--- a/binaries/cuprated/src/rpc/json.rs
+++ b/binaries/cuprated/src/rpc/json.rs
@@ -1073,7 +1073,7 @@ fn add_aux_pow_inner(
         for nonce in 0..=MAX_NONCE {
             for i in &mut slots {
                 let slot_u32 = get_aux_slot(
-                    &aux_pow[u32_to_usize(*i)].id,
+                    &aux_pow[u32_to_usize(*i)].id.0,
                     nonce,
                     non_zero_len.try_into().unwrap(),
                 );
@@ -1117,8 +1117,8 @@ fn add_aux_pow_inner(
                 return Err(anyhow!("Slot value out of range"));
             }
 
-            aux_pow_id_raw.push(aux_pow.id);
-            aux_pow_raw.push(aux_pow.hash);
+            aux_pow_id_raw.push(aux_pow.id.0);
+            aux_pow_raw.push(aux_pow.hash.0);
         }
 
         assert_eq!(
@@ -1139,8 +1139,8 @@ fn add_aux_pow_inner(
                 return Err(anyhow!("Slot value out of range"));
             }
 
-            aux_pow_raw[slot] = aux_pow.hash;
-            aux_pow_id_raw[slot] = aux_pow.id;
+            aux_pow_raw[slot] = aux_pow.hash.0;
+            aux_pow_id_raw[slot] = aux_pow.id.0;
         }
 
         (
@@ -1197,9 +1197,7 @@ fn add_aux_pow_inner(
     let blocktemplate_blob = hex::encode(blocktemplate_blob);
     let blockhashing_blob = hex::encode(blockhashing_blob);
     let merkle_root = hex::encode(merkle_root);
-    let aux_pow = IntoIterator::into_iter(aux_pow) // must be explicit due to `boxed_slice_into_iter`
-        .map(Into::into)
-        .collect::<Vec<cuprate_rpc_types::misc::AuxPow>>();
+    let aux_pow = aux_pow.into_vec();
 
     Ok(AddAuxPowResponse {
         base: ResponseBase::OK,
diff --git a/helper/Cargo.toml b/helper/Cargo.toml
index 716beb34..7ebbf8a0 100644
--- a/helper/Cargo.toml
+++ b/helper/Cargo.toml
@@ -23,6 +23,7 @@ map       = ["cast", "dep:monero-serai", "dep:cuprate-constants"]
 time      = ["dep:chrono", "std"]
 thread    = ["std", "dep:target_os_lib"]
 tx        = ["dep:monero-serai"]
+fmt       = ["map"]
 
 [dependencies]
 cuprate-constants = { workspace = true, optional = true, features = ["block"] }
diff --git a/helper/src/fmt.rs b/helper/src/fmt.rs
new file mode 100644
index 00000000..d5c043e3
--- /dev/null
+++ b/helper/src/fmt.rs
@@ -0,0 +1,19 @@
+//! Formatting.
+
+use crate::map::combine_low_high_bits_to_u128;
+
+/// Format two [`u64`]'s as a [`u128`] as a lower-case hexadecimal string prefixed with `0x`.
+///
+/// ```rust
+/// # use cuprate_helper::fmt::hex_prefix_u128;
+/// assert_eq!(hex_prefix_u128(0, 0), "0x0");
+/// assert_eq!(hex_prefix_u128(0, u64::MAX), "0xffffffffffffffff0000000000000000");
+/// assert_eq!(hex_prefix_u128(u64::MAX, 0), "0xffffffffffffffff");
+/// assert_eq!(hex_prefix_u128(u64::MAX, u64::MAX), "0xffffffffffffffffffffffffffffffff");
+/// ```
+pub fn hex_prefix_u128(low_bits: u64, high_bits: u64) -> String {
+    format!("{:#x}", combine_low_high_bits_to_u128(low_bits, high_bits))
+}
+
+#[cfg(test)]
+mod tests {}
diff --git a/helper/src/lib.rs b/helper/src/lib.rs
index 9bd64fa1..7142bd90 100644
--- a/helper/src/lib.rs
+++ b/helper/src/lib.rs
@@ -33,6 +33,6 @@ pub mod tx;
 
 #[cfg(feature = "crypto")]
 pub mod crypto;
-//---------------------------------------------------------------------------------------------------- Private Usage
 
-//----------------------------------------------------------------------------------------------------
+#[cfg(feature = "fmt")]
+pub mod fmt;
diff --git a/helper/src/map.rs b/helper/src/map.rs
index b719f8fb..8f72e50e 100644
--- a/helper/src/map.rs
+++ b/helper/src/map.rs
@@ -5,6 +5,8 @@
 //! `#[no_std]` compatible.
 
 //---------------------------------------------------------------------------------------------------- Use
+use core::net::Ipv4Addr;
+
 use monero_serai::transaction::Timelock;
 
 use cuprate_constants::block::MAX_BLOCK_HEIGHT;
@@ -28,6 +30,7 @@ use crate::cast::{u64_to_usize, usize_to_u64};
 /// let high = u64::MAX;
 ///
 /// assert_eq!(split_u128_into_low_high_bits(value), (low, high));
+/// assert_eq!(split_u128_into_low_high_bits(0), (0, 0));
 /// ```
 #[inline]
 pub const fn split_u128_into_low_high_bits(value: u128) -> (u64, u64) {
@@ -52,6 +55,7 @@ pub const fn split_u128_into_low_high_bits(value: u128) -> (u64, u64) {
 /// let high = u64::MAX;
 ///
 /// assert_eq!(combine_low_high_bits_to_u128(low, high), value);
+/// assert_eq!(combine_low_high_bits_to_u128(0, 0), 0);
 /// ```
 #[inline]
 pub const fn combine_low_high_bits_to_u128(low_bits: u64, high_bits: u64) -> u128 {
@@ -59,6 +63,24 @@ pub const fn combine_low_high_bits_to_u128(low_bits: u64, high_bits: u64) -> u12
     res | (low_bits as u128)
 }
 
+//---------------------------------------------------------------------------------------------------- IPv4
+/// Convert an [`Ipv4Addr`] to a [`u32`].
+///
+/// For why this exists, see: <https://architecture.cuprate.org/oddities/le-ipv4.html>.
+#[inline]
+pub const fn ipv4_from_u32(ip: u32) -> Ipv4Addr {
+    let [a, b, c, d] = ip.to_le_bytes();
+    Ipv4Addr::new(a, b, c, d)
+}
+
+/// Convert a [`u32`] to an [`Ipv4Addr`].
+///
+/// For why this exists, see: <https://architecture.cuprate.org/oddities/le-ipv4.html>.
+#[inline]
+pub const fn u32_from_ipv4(ip: Ipv4Addr) -> u32 {
+    u32::from_le_bytes(ip.octets())
+}
+
 //---------------------------------------------------------------------------------------------------- Timelock
 /// Map a [`u64`] to a [`Timelock`].
 ///
diff --git a/rpc/types/Cargo.toml b/rpc/types/Cargo.toml
index 1f4e62bc..55fac9cd 100644
--- a/rpc/types/Cargo.toml
+++ b/rpc/types/Cargo.toml
@@ -12,7 +12,13 @@ keywords    = ["cuprate", "rpc", "types", "monero"]
 default = ["serde", "epee", "from"]
 serde   = ["dep:serde", "cuprate-fixed-bytes/serde", "cuprate-types/serde"]
 epee    = ["dep:cuprate-epee-encoding", "cuprate-types/epee"]
-from    = ["dep:cuprate-helper", "cuprate-helper/map", "dep:cuprate-p2p-core", "dep:hex"]
+from    = [
+	"dep:cuprate-helper",
+	"cuprate-helper/map",
+	"cuprate-helper/fmt",
+	"dep:cuprate-p2p-core",
+	"dep:hex"
+]
 
 [dependencies]
 cuprate-epee-encoding = { workspace = true, optional = true }
diff --git a/rpc/types/src/from.rs b/rpc/types/src/from.rs
index 6d8ceec5..6d374dfc 100644
--- a/rpc/types/src/from.rs
+++ b/rpc/types/src/from.rs
@@ -2,39 +2,24 @@
 //!
 //! Only non-crate types are imported, all crate types use `crate::`.
 
-#![allow(unused_variables, unreachable_code, reason = "TODO")]
-
 use std::{
     net::{Ipv4Addr, SocketAddr, SocketAddrV4},
     time::Duration,
 };
 
-use cuprate_helper::map::combine_low_high_bits_to_u128;
+use cuprate_helper::{
+    fmt::hex_prefix_u128,
+    map::{combine_low_high_bits_to_u128, ipv4_from_u32},
+};
 use cuprate_p2p_core::{
-    types::{BanState, ConnectionId, ConnectionInfo, SetBan, Span},
-    ClearNet, NetZoneAddress, NetworkZone,
+    types::{ConnectionId, ConnectionInfo, SetBan, Span},
+    NetZoneAddress,
 };
 use cuprate_types::{
     hex::Hex,
-    rpc::{
-        AuxPow, BlockHeader, BlockOutputIndices, ChainInfo, GetBan, GetMinerDataTxBacklogEntry,
-        GetOutputsOut, HardforkEntry, HistogramEntry, OutKey, OutKeyBin, OutputDistributionData,
-        Peer, PublicNode, SpentKeyImageInfo, TxBacklogEntry, TxInfo, TxOutputIndices, TxpoolHisto,
-        TxpoolStats,
-    },
+    rpc::{BlockHeader, ChainInfo, HistogramEntry, TxInfo},
 };
 
-/// <https://architecture.cuprate.org/oddities/le-ipv4.html>
-const fn ipv4_from_u32(ip: u32) -> Ipv4Addr {
-    let [a, b, c, d] = ip.to_le_bytes();
-    Ipv4Addr::new(a, b, c, d)
-}
-
-/// Format two [`u64`]'s as a [`u128`] as a hexadecimal string prefixed with `0x`.
-fn hex_prefix_u128(low: u64, high: u64) -> String {
-    format!("{:#x}", combine_low_high_bits_to_u128(low, high))
-}
-
 impl From<BlockHeader> for crate::misc::BlockHeader {
     fn from(x: BlockHeader) -> Self {
         Self {
@@ -54,7 +39,7 @@ impl From<BlockHeader> for crate::misc::BlockHeader {
             nonce: x.nonce,
             num_txes: x.num_txes,
             orphan_status: x.orphan_status,
-            pow_hash: Hex(x.pow_hash),
+            pow_hash: x.pow_hash.map_or_else(String::new, hex::encode),
             prev_hash: Hex(x.prev_hash),
             reward: x.reward,
             timestamp: x.timestamp,
@@ -206,25 +191,3 @@ impl From<TxInfo> for crate::misc::TxInfo {
         }
     }
 }
-
-impl From<AuxPow> for crate::misc::AuxPow {
-    fn from(x: AuxPow) -> Self {
-        Self {
-            id: Hex(x.id),
-            hash: Hex(x.hash),
-        }
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn hex() {
-        assert_eq!(hex_prefix_u128(0, 0), "0x0");
-        assert_eq!(hex_prefix_u128(0, u64::MAX), "0x0");
-        assert_eq!(hex_prefix_u128(u64::MAX, 0), "0x0");
-        assert_eq!(hex_prefix_u128(u64::MAX, u64::MAX), "0x0");
-    }
-}
diff --git a/rpc/types/src/json.rs b/rpc/types/src/json.rs
index 8f687268..4d51252a 100644
--- a/rpc/types/src/json.rs
+++ b/rpc/types/src/json.rs
@@ -6,14 +6,14 @@
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 
-use cuprate_types::rpc::{GetMinerDataTxBacklogEntry, HardforkEntry, TxBacklogEntry};
+use cuprate_types::rpc::{AuxPow, GetMinerDataTxBacklogEntry, HardforkEntry, TxBacklogEntry};
 
 use crate::{
     base::{AccessResponseBase, ResponseBase},
     macros::define_request_and_response,
     misc::{
-        AuxPow, BlockHeader, ChainInfo, ConnectionInfo, Distribution, GetBan, HistogramEntry,
-        SetBan, Span, Status, SyncInfoPeer,
+        BlockHeader, ChainInfo, ConnectionInfo, Distribution, GetBan, HistogramEntry, SetBan, Span,
+        Status, SyncInfoPeer,
     },
     rpc_call::RpcCallValue,
 };
diff --git a/rpc/types/src/misc/mod.rs b/rpc/types/src/misc/mod.rs
index 0d616210..b81bf9c8 100644
--- a/rpc/types/src/misc/mod.rs
+++ b/rpc/types/src/misc/mod.rs
@@ -27,6 +27,6 @@ pub use requested_info::RequestedInfo;
 pub use status::Status;
 pub use tx_entry::TxEntry;
 pub use types::{
-    AuxPow, BlockHeader, ChainInfo, ConnectionInfo, GetBan, GetOutputsOut, HistogramEntry,
-    OutKeyBin, SetBan, Span, SpentKeyImageInfo, SyncInfoPeer, TxInfo,
+    BlockHeader, ChainInfo, ConnectionInfo, GetBan, GetOutputsOut, HistogramEntry, OutKeyBin,
+    SetBan, Span, SpentKeyImageInfo, SyncInfoPeer, TxInfo,
 };
diff --git a/rpc/types/src/misc/types.rs b/rpc/types/src/misc/types.rs
index 49bd8517..82227121 100644
--- a/rpc/types/src/misc/types.rs
+++ b/rpc/types/src/misc/types.rs
@@ -90,7 +90,8 @@ define_struct_and_impl_epee! {
         nonce: u32,
         num_txes: u64,
         orphan_status: bool,
-        pow_hash: Hex<32>,
+        /// This is an empty string if the `fill_pow_hash` param is `false`.
+        pow_hash: String,
         prev_hash: Hex<32>,
         reward: u64,
         timestamp: u64,
@@ -309,18 +310,6 @@ define_struct_and_impl_epee! {
     }
 }
 
-define_struct_and_impl_epee! {
-    #[doc = monero_definition_link!(
-        "cc73fe71162d564ffda8e549b79a350bca53c454",
-        "rpc/core_rpc_server_commands_defs.h",
-        1070..=1079
-    )]
-    AuxPow {
-        id: Hex<32>,
-        hash: Hex<32>,
-    }
-}
-
 //---------------------------------------------------------------------------------------------------- Tests
 #[cfg(test)]
 mod test {}
diff --git a/types/src/rpc/types.rs b/types/src/rpc/types.rs
index a9ac06fc..2939b355 100644
--- a/types/src/rpc/types.rs
+++ b/types/src/rpc/types.rs
@@ -103,7 +103,8 @@ define_struct_and_impl_epee! {
         nonce: u32,
         num_txes: u64,
         orphan_status: bool,
-        pow_hash: [u8; 32],
+        /// This is [`None`] if the `fill_pow_hash` param is `false`.
+        pow_hash: Option<[u8; 32]>,
         prev_hash: [u8; 32],
         reward: u64,
         timestamp: u64,
@@ -273,8 +274,8 @@ define_struct_and_impl_epee! {
         1070..=1079
     )]
     AuxPow {
-        id: [u8; 32],
-        hash: [u8; 32],
+        id: Hex<32>,
+        hash: Hex<32>,
     }
 
     #[doc = monero_definition_link!(