diff --git a/Cargo.lock b/Cargo.lock
index cc31add..ab055f2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -40,17 +40,6 @@ dependencies = [
  "embedded-hal",
 ]
 
-[[package]]
-name = "atty"
-version = "0.2.14"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
-dependencies = [
- "hermit-abi",
- "libc",
- "winapi",
-]
-
 [[package]]
 name = "autocfg"
 version = "1.0.1"
@@ -96,24 +85,6 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c147d86912d04bef727828fda769a76ca81629a46d8ba311a8d58a26aa91473d"
 
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a40b47ad93e1a5404e6c18dec46b628214fee441c70f4ab5d6942142cc268a3d"
-dependencies = [
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- "memchr",
- "regex-automata",
- "serde",
-]
-
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "099e596ef14349721d9016f6b80dd3419ea1bf289ab9b44df8e4dfd3a005d5d9"
-
 [[package]]
 name = "byteorder"
 version = "1.4.2"
@@ -135,23 +106,6 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
-[[package]]
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-dependencies = [
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- "textwrap",
- "unicode-width",
-]
-
-[[package]]
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-checksum = "28b9d6de7f49e22cf97ad17fc4036ece69300032f45f78f30b4a4482cdc3f4a6"
-
 [[package]]
 name = "cortex-m"
 version = "0.6.7"
@@ -244,110 +198,6 @@ dependencies = [
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 ]
 
-[[package]]
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-version = "0.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
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- "csv",
- "itertools 0.10.0",
- "lazy_static",
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- "oorandom",
- "plotters",
- "rayon",
- "regex",
- "serde",
- "serde_cbor",
- "serde_derive",
- "serde_json",
- "tinytemplate",
- "walkdir",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e022feadec601fba1649cfa83586381a4ad31c6bf3a9ab7d408118b05dd9889d"
-dependencies = [
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- "itertools 0.9.0",
-]
-
-[[package]]
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-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
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-dependencies = [
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- "crossbeam-utils",
-]
-
-[[package]]
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-checksum = "94af6efb46fef72616855b036a624cf27ba656ffc9be1b9a3c931cfc7749a9a9"
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- "crossbeam-utils",
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-
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-dependencies = [
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- "const_fn",
- "crossbeam-utils",
- "lazy_static",
- "memoffset",
- "scopeguard",
-]
-
-[[package]]
-name = "crossbeam-utils"
-version = "0.8.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02d96d1e189ef58269ebe5b97953da3274d83a93af647c2ddd6f9dab28cedb8d"
-dependencies = [
- "autocfg",
- "cfg-if",
- "lazy_static",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f9d58633299b24b515ac72a3f869f8b91306a3cec616a602843a383acd6f9e97"
-dependencies = [
- "bstr",
- "csv-core",
- "itoa",
- "ryu",
- "serde",
-]
-
-[[package]]
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-checksum = "2b2466559f260f48ad25fe6317b3c8dac77b5bdb5763ac7d9d6103530663bc90"
-dependencies = [
- "memchr",
-]
-
 [[package]]
 name = "derive_stringset"
 version = "0.1.0"
@@ -362,7 +212,6 @@ dependencies = [
 name = "dsp"
 version = "0.1.0"
 dependencies = [
- "criterion",
  "generic-array 0.14.4",
  "libm",
  "miniconf",
@@ -371,12 +220,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "either"
-version = "1.6.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
-
 [[package]]
 name = "embedded-dma"
 version = "0.1.2"
@@ -466,12 +309,6 @@ dependencies = [
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 ]
 
-[[package]]
-name = "half"
-version = "1.7.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "62aca2aba2d62b4a7f5b33f3712cb1b0692779a56fb510499d5c0aa594daeaf3"
-
 [[package]]
 name = "hash32"
 version = "0.1.1"
@@ -500,15 +337,6 @@ dependencies = [
  "stable_deref_trait",
 ]
 
-[[package]]
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-version = "0.1.18"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "322f4de77956e22ed0e5032c359a0f1273f1f7f0d79bfa3b8ffbc730d7fbcc5c"
-dependencies = [
- "libc",
-]
-
 [[package]]
 name = "indexmap"
 version = "1.6.1"
@@ -519,45 +347,6 @@ dependencies = [
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 ]
 
-[[package]]
-name = "itertools"
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "284f18f85651fe11e8a991b2adb42cb078325c996ed026d994719efcfca1d54b"
-dependencies = [
- "either",
-]
-
-[[package]]
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-checksum = "37d572918e350e82412fe766d24b15e6682fb2ed2bbe018280caa810397cb319"
-dependencies = [
- "either",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd25036021b0de88a0aff6b850051563c6516d0bf53f8638938edbb9de732736"
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
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-dependencies = [
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-
-[[package]]
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-
 [[package]]
 name = "libc"
 version = "0.2.86"
@@ -602,21 +391,6 @@ dependencies = [
  "embedded-hal",
 ]
 
-[[package]]
-name = "memchr"
-version = "2.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
-
-[[package]]
-name = "memoffset"
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-checksum = "157b4208e3059a8f9e78d559edc658e13df41410cb3ae03979c83130067fdd87"
-dependencies = [
- "autocfg",
-]
-
 [[package]]
 name = "miniconf"
 version = "0.1.0"
@@ -704,22 +478,6 @@ dependencies = [
  "autocfg",
 ]
 
-[[package]]
-name = "num_cpus"
-version = "1.13.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "05499f3756671c15885fee9034446956fff3f243d6077b91e5767df161f766b3"
-dependencies = [
- "hermit-abi",
- "libc",
-]
-
-[[package]]
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-version = "11.1.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ab1bc2a289d34bd04a330323ac98a1b4bc82c9d9fcb1e66b63caa84da26b575"
-
 [[package]]
 name = "panic-halt"
 version = "0.2.0"
@@ -742,34 +500,6 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c5d65c4d95931acda4498f675e332fcbdc9a06705cd07086c510e9b6009cd1c1"
 
-[[package]]
-name = "plotters"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "45ca0ae5f169d0917a7c7f5a9c1a3d3d9598f18f529dd2b8373ed988efea307a"
-dependencies = [
- "num-traits",
- "plotters-backend",
- "plotters-svg",
- "wasm-bindgen",
- "web-sys",
-]
-
-[[package]]
-name = "plotters-backend"
-version = "0.3.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b07fffcddc1cb3a1de753caa4e4df03b79922ba43cf882acc1bdd7e8df9f4590"
-
-[[package]]
-name = "plotters-svg"
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-checksum = "b38a02e23bd9604b842a812063aec4ef702b57989c37b655254bb61c471ad211"
-dependencies = [
- "plotters-backend",
-]
-
 [[package]]
 name = "ppv-lite86"
 version = "0.2.10"
@@ -846,55 +576,6 @@ version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "60a357793950651c4ed0f3f52338f53b2f809f32d83a07f72909fa13e4c6c1e3"
 
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8b0d8e0819fadc20c74ea8373106ead0600e3a67ef1fe8da56e39b9ae7275674"
-dependencies = [
- "autocfg",
- "crossbeam-deque",
- "either",
- "rayon-core",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ab346ac5921dc62ffa9f89b7a773907511cdfa5490c572ae9be1be33e8afa4a"
-dependencies = [
- "crossbeam-channel",
- "crossbeam-deque",
- "crossbeam-utils",
- "lazy_static",
- "num_cpus",
-]
-
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-checksum = "d9251239e129e16308e70d853559389de218ac275b515068abc96829d05b948a"
-dependencies = [
- "regex-syntax",
-]
-
-[[package]]
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-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ae1ded71d66a4a97f5e961fd0cb25a5f366a42a41570d16a763a69c092c26ae4"
-dependencies = [
- "byteorder",
-]
-
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-checksum = "b5eb417147ba9860a96cfe72a0b93bf88fee1744b5636ec99ab20c1aa9376581"
-
 [[package]]
 name = "rtic-core"
 version = "0.3.1"
@@ -921,27 +602,6 @@ dependencies = [
  "semver",
 ]
 
-[[package]]
-name = "ryu"
-version = "1.0.5"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
-
-[[package]]
-name = "same-file"
-version = "1.0.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "93fc1dc3aaa9bfed95e02e6eadabb4baf7e3078b0bd1b4d7b6b0b68378900502"
-dependencies = [
- "winapi-util",
-]
-
-[[package]]
-name = "scopeguard"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
-
 [[package]]
 name = "semver"
 version = "0.9.0"
@@ -976,16 +636,6 @@ dependencies = [
  "serde",
 ]
 
-[[package]]
-name = "serde_cbor"
-version = "0.11.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1e18acfa2f90e8b735b2836ab8d538de304cbb6729a7360729ea5a895d15a622"
-dependencies = [
- "half",
- "serde",
-]
-
 [[package]]
 name = "serde_derive"
 version = "1.0.123"
@@ -997,17 +647,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "serde_json"
-version = "1.0.62"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ea1c6153794552ea7cf7cf63b1231a25de00ec90db326ba6264440fa08e31486"
-dependencies = [
- "itoa",
- "ryu",
- "serde",
-]
-
 [[package]]
 name = "smoltcp"
 version = "0.7.0"
@@ -1103,37 +742,12 @@ dependencies = [
  "unicode-xid",
 ]
 
-[[package]]
-name = "textwrap"
-version = "0.11.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
-dependencies = [
- "unicode-width",
-]
-
-[[package]]
-name = "tinytemplate"
-version = "1.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a2ada8616fad06a2d0c455adc530de4ef57605a8120cc65da9653e0e9623ca74"
-dependencies = [
- "serde",
- "serde_json",
-]
-
 [[package]]
 name = "typenum"
 version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "373c8a200f9e67a0c95e62a4f52fbf80c23b4381c05a17845531982fa99e6b33"
 
-[[package]]
-name = "unicode-width"
-version = "0.1.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
-
 [[package]]
 name = "unicode-xid"
 version = "0.2.1"
@@ -1167,114 +781,8 @@ dependencies = [
  "vcell",
 ]
 
-[[package]]
-name = "walkdir"
-version = "2.3.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "777182bc735b6424e1a57516d35ed72cb8019d85c8c9bf536dccb3445c1a2f7d"
-dependencies = [
- "same-file",
- "winapi",
- "winapi-util",
-]
-
 [[package]]
 name = "wasi"
 version = "0.10.2+wasi-snapshot-preview1"
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 checksum = "fd6fbd9a79829dd1ad0cc20627bf1ed606756a7f77edff7b66b7064f9cb327c6"
-
-[[package]]
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-version = "0.2.70"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "55c0f7123de74f0dab9b7d00fd614e7b19349cd1e2f5252bbe9b1754b59433be"
-dependencies = [
- "cfg-if",
- "wasm-bindgen-macro",
-]
-
-[[package]]
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-dependencies = [
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- "lazy_static",
- "log",
- "proc-macro2",
- "quote",
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-
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-
-[[package]]
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- "winapi-x86_64-pc-windows-gnu",
-]
-
-[[package]]
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-
-[[package]]
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-dependencies = [
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-[[package]]
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diff --git a/dsp/Cargo.toml b/dsp/Cargo.toml
index 457e209..78f27c2 100644
--- a/dsp/Cargo.toml
+++ b/dsp/Cargo.toml
@@ -14,7 +14,7 @@ git = "https://github.com/quartiq/miniconf.git"
 branch = "rs/issue-21/terminal-array-elements"
 
 [dev-dependencies]
-criterion = "0.3"
+# criterion = "0.3"
 rand = "0.8"
 ndarray = "0.14"
 
@@ -22,5 +22,10 @@ ndarray = "0.14"
 name = "micro"
 harness = false
 
+# Note: Due to a dependency injection bug, criterion enables std-features for serde, which breaks
+# testing. Patch serde to not use std dependencies.
+[patch.crates-io]
+serde = { version = "1.0", features = ["derive"], default-features = false }
+
 [features]
 nightly = []
diff --git a/src/bin/dual-iir.rs b/src/bin/dual-iir.rs
index e536939..b10f57d 100644
--- a/src/bin/dual-iir.rs
+++ b/src/bin/dual-iir.rs
@@ -26,6 +26,7 @@ const IIR_CASCADE_LENGTH: usize = 1;
 #[derive(Debug, Deserialize, StringSet)]
 pub struct Settings {
     afe: [AfeGain; 2],
+    update_state: bool,
     iir_state: [[iir::Vec5; IIR_CASCADE_LENGTH]; 2],
     iir_ch: [[iir::IIR; IIR_CASCADE_LENGTH]; 2],
 }
@@ -34,6 +35,7 @@ impl Default for Settings {
     fn default() -> Self {
         Self {
             afe: [AfeGain::G1, AfeGain::G1],
+             update_state: false,
             iir_state: [[[0.; 5]; IIR_CASCADE_LENGTH]; 2],
             iir_ch: [[iir::IIR::new(1., -SCALE, SCALE); IIR_CASCADE_LENGTH]; 2],
         }
@@ -173,8 +175,10 @@ const APP: () = {
         // Update the IIR channels.
         c.resources.iir_ch.lock(|iir| *iir = settings.iir_ch);
 
-        // Update the IIR states.
-        c.resources.iir_state.lock(|iir| *iir = settings.iir_state);
+        // Update the IIR states only if explicitly requested.
+        if settings.update_state {
+            c.resources.iir_state.lock(|iir| *iir = settings.iir_state);
+        }
 
         // Update AFEs
         c.resources.afes.0.set_gain(settings.afe[0]);