diff --git a/Makefile b/Makefile
index 9764b3528..9090c3ef0 100644
--- a/Makefile
+++ b/Makefile
@@ -48,11 +48,11 @@ install_test:
 
 test: $(PY_SPEC_ALL_TARGETS)
 	cd $(PY_SPEC_DIR); . venv/bin/activate;	export PYTHONPATH="./"; \
-	python -m pytest --cov=eth2spec.phase0.spec --cov=eth2spec.phase1.spec --cov-report="html:$(COV_HTML_OUT)" --cov-branch eth2spec
+	python -m pytest -n 4 --cov=eth2spec.phase0.spec --cov=eth2spec.phase1.spec --cov-report="html:$(COV_HTML_OUT)" --cov-branch eth2spec
 
 citest: $(PY_SPEC_ALL_TARGETS)
 	cd $(PY_SPEC_DIR); mkdir -p test-reports/eth2spec; . venv/bin/activate; \
-	python -m pytest --junitxml=test-reports/eth2spec/test_results.xml eth2spec
+	python -m pytest -n 4 --junitxml=test-reports/eth2spec/test_results.xml eth2spec
 
 open_cov:
 	((open "$(COV_INDEX_FILE)" || xdg-open "$(COV_INDEX_FILE)") &> /dev/null) &
diff --git a/configs/constant_presets/minimal.yaml b/configs/constant_presets/minimal.yaml
index edc73ab8b..434abef53 100644
--- a/configs/constant_presets/minimal.yaml
+++ b/configs/constant_presets/minimal.yaml
@@ -66,8 +66,8 @@ SLOTS_PER_HISTORICAL_ROOT: 64
 MIN_VALIDATOR_WITHDRAWABILITY_DELAY: 256
 # 2**11 (= 2,048) epochs
 PERSISTENT_COMMITTEE_PERIOD: 2048
-# 2**6 (= 64) epochs
-MAX_EPOCHS_PER_CROSSLINK: 64
+# [customized] fast catchup crosslinks
+MAX_EPOCHS_PER_CROSSLINK: 4
 # 2**2 (= 4) epochs
 MIN_EPOCHS_TO_INACTIVITY_PENALTY: 4
 # [customized] 2**12 (= 4,096) epochs
diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index c94c4fcc9..bb1379b93 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -201,7 +201,7 @@ These configurations are updated for releases, but may be out of sync during `de
 ### Gwei values
 
 | Name | Value |
-| - | - | :-: |
+| - | - |
 | `MIN_DEPOSIT_AMOUNT` | `Gwei(2**0 * 10**9)` (= 1,000,000,000) |
 | `MAX_EFFECTIVE_BALANCE` | `Gwei(2**5 * 10**9)` (= 32,000,000,000) |
 | `EJECTION_BALANCE` | `Gwei(2**4 * 10**9)` (= 16,000,000,000) |
diff --git a/test_libs/pyspec/requirements-testing.txt b/test_libs/pyspec/requirements-testing.txt
index ad9c4de3b..b5229ae20 100644
--- a/test_libs/pyspec/requirements-testing.txt
+++ b/test_libs/pyspec/requirements-testing.txt
@@ -1,6 +1,7 @@
 -r requirements.txt
-pytest>=3.6,<3.7
+pytest>=4.4
 ../config_helpers
 flake8==3.7.7
 mypy==0.701
 pytest-cov
+pytest-xdist