diff --git a/Makefile b/Makefile
index 05c6c74d5..89362d12d 100644
--- a/Makefile
+++ b/Makefile
@@ -38,15 +38,24 @@ PROFILE ?= release
 # they run for different forks.
 FORKS=phase0 altair merge capella
 
+# Extra flags for Cargo
+CARGO_INSTALL_EXTRA_FLAGS?=
+
 # Builds the Lighthouse binary in release (optimized).
 #
 # Binaries will most likely be found in `./target/release`
 install:
-	cargo install --path lighthouse --force --locked --features "$(FEATURES)" --profile "$(PROFILE)"
+	cargo install --path lighthouse --force --locked \
+		--features "$(FEATURES)" \
+		--profile "$(PROFILE)" \
+		$(CARGO_INSTALL_EXTRA_FLAGS)
 
 # Builds the lcli binary in release (optimized).
 install-lcli:
-	cargo install --path lcli --force --locked --features "$(FEATURES)" --profile "$(PROFILE)"
+	cargo install --path lcli --force --locked \
+		--features "$(FEATURES)" \
+		--profile "$(PROFILE)" \
+		$(CARGO_INSTALL_EXTRA_FLAGS)
 
 # The following commands use `cross` to build a cross-compile.
 #
@@ -124,7 +133,7 @@ run-ef-tests:
 test-beacon-chain: $(patsubst %,test-beacon-chain-%,$(FORKS))
 
 test-beacon-chain-%:
-	env FORK_NAME=$* cargo test --release --features fork_from_env -p beacon_chain
+	env FORK_NAME=$* cargo test --release --features fork_from_env,slasher/lmdb -p beacon_chain
 
 # Run the tests in the `operation_pool` crate for all known forks.
 test-op-pool: $(patsubst %,test-op-pool-%,$(FORKS))
diff --git a/beacon_node/Cargo.toml b/beacon_node/Cargo.toml
index a2acd6055..3c37f41de 100644
--- a/beacon_node/Cargo.toml
+++ b/beacon_node/Cargo.toml
@@ -36,7 +36,7 @@ clap_utils = { path = "../common/clap_utils" }
 hyper = "0.14.4"
 lighthouse_version = { path = "../common/lighthouse_version" }
 hex = "0.4.2"
-slasher = { path = "../slasher" }
+slasher = { path = "../slasher", default-features = false }
 monitoring_api = { path = "../common/monitoring_api" }
 sensitive_url = { path = "../common/sensitive_url" }
 http_api = { path = "http_api" }
diff --git a/beacon_node/beacon_chain/Cargo.toml b/beacon_node/beacon_chain/Cargo.toml
index 5b8583304..5599e6f97 100644
--- a/beacon_node/beacon_chain/Cargo.toml
+++ b/beacon_node/beacon_chain/Cargo.toml
@@ -53,7 +53,7 @@ fork_choice = { path = "../../consensus/fork_choice" }
 task_executor = { path = "../../common/task_executor" }
 derivative = "2.1.1"
 itertools = "0.10.0"
-slasher = { path = "../../slasher" }
+slasher = { path = "../../slasher", default-features = false }
 eth2 = { path = "../../common/eth2" }
 strum = { version = "0.24.0", features = ["derive"] }
 logging = { path = "../../common/logging" }
diff --git a/beacon_node/client/Cargo.toml b/beacon_node/client/Cargo.toml
index 9a49843a9..876458eea 100644
--- a/beacon_node/client/Cargo.toml
+++ b/beacon_node/client/Cargo.toml
@@ -39,7 +39,7 @@ time = "0.3.5"
 directory = {path = "../../common/directory"}
 http_api = { path = "../http_api" }
 http_metrics = { path = "../http_metrics" }
-slasher = { path = "../../slasher" }
+slasher = { path = "../../slasher", default-features = false }
 slasher_service = { path = "../../slasher/service" }
 monitoring_api = {path = "../../common/monitoring_api"}
 execution_layer = { path = "../execution_layer" }
diff --git a/book/src/installation-source.md b/book/src/installation-source.md
index 8e515a41b..c89dd1add 100644
--- a/book/src/installation-source.md
+++ b/book/src/installation-source.md
@@ -133,6 +133,15 @@ Commonly used features include:
 * `slasher-lmdb`: support for the LMDB slasher backend.
 * `jemalloc`: use [`jemalloc`][jemalloc] to allocate memory. Enabled by default on Linux and macOS.
   Not supported on Windows.
+* `spec-minimal`: support for the minimal preset (useful for testing).
+
+Default features (e.g. `slasher-mdbx`) may be opted out of using the `--no-default-features`
+argument for `cargo`, which can plumbed in via the `CARGO_INSTALL_EXTRA_FLAGS` environment variable.
+E.g.
+
+```
+CARGO_INSTALL_EXTRA_FLAGS="--no-default-features" make
+```
 
 [jemalloc]: https://jemalloc.net/
 
diff --git a/lighthouse/Cargo.toml b/lighthouse/Cargo.toml
index 2c0f1ec1c..ecac53fb1 100644
--- a/lighthouse/Cargo.toml
+++ b/lighthouse/Cargo.toml
@@ -55,7 +55,7 @@ malloc_utils = { path = "../common/malloc_utils" }
 directory = { path = "../common/directory" }
 unused_port = { path = "../common/unused_port" }
 database_manager = { path = "../database_manager" }
-slasher = { path = "../slasher" }
+slasher = { path = "../slasher", default-features = false }
 
 [dev-dependencies]
 tempfile = "3.1.0"
diff --git a/slasher/service/Cargo.toml b/slasher/service/Cargo.toml
index 63cf1e464..0a787defa 100644
--- a/slasher/service/Cargo.toml
+++ b/slasher/service/Cargo.toml
@@ -9,7 +9,7 @@ beacon_chain = { path = "../../beacon_node/beacon_chain" }
 directory = { path = "../../common/directory" }
 lighthouse_network = { path = "../../beacon_node/lighthouse_network" }
 network = { path = "../../beacon_node/network" }
-slasher = { path = ".." }
+slasher = { path = "..", default-features = false }
 slog = "2.5.2"
 slot_clock = { path = "../../common/slot_clock" }
 state_processing = { path = "../../consensus/state_processing" }