diff --git a/.gitmodules b/.gitmodules
index 607a141ce..e6c2a4929 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -43,11 +43,6 @@
 	url = https://github.com/status-im/nim-http-utils.git
 	ignore = dirty
 	branch = master
-[submodule "vendor/nim-asyncdispatch2"]
-	path = vendor/nim-asyncdispatch2
-	url = https://github.com/status-im/nim-asyncdispatch2.git
-	ignore = dirty
-	branch = master
 [submodule "vendor/nim-json-rpc"]
 	path = vendor/nim-json-rpc
 	url = https://github.com/status-im/nim-json-rpc.git
@@ -118,3 +113,8 @@
 	url = https://github.com/nim-lang/nimble.git
 	ignore = dirty
 	branch = master
+[submodule "vendor/nim-chronos"]
+	path = vendor/nim-chronos
+	url = https://github.com/status-im/nim-chronos.git
+	ignore = dirty
+	branch = master
diff --git a/Makefile b/Makefile
index 159bf1372..0bf4ab484 100644
--- a/Makefile
+++ b/Makefile
@@ -14,20 +14,48 @@ GIT_STATUS := git status
 #- duplicated in "env.sh" for the env var with the same name
 NIMBLE_DIR := vendor/.nimble
 REPOS_DIR := vendor
+ifeq ($(OS), Windows_NT)
+  PWD := pwd -W
+else
+  PWD := pwd
+endif
 # we want a "recursively expanded" (delayed interpolation) variable here, so we can set CMD in rule recipes
-RUN_CMD_IN_ALL_REPOS = git submodule foreach --recursive --quiet 'echo -e "\n\e[32m$$name:\e[39m"; $(CMD)'; echo -e "\n\e[32m$$(pwd):\e[39m"; $(CMD)
+RUN_CMD_IN_ALL_REPOS = git submodule foreach --recursive --quiet 'echo -e "\n\e[32m$$name:\e[39m"; $(CMD)'; echo -e "\n\e[32m$$($(PWD)):\e[39m"; $(CMD)
 # absolute path, since it will be run at various subdirectory depths
 ENV_SCRIPT := "$(CURDIR)/env.sh"
 # duplicated in "env.sh" to prepend NIM_DIR/bin to PATH
 NIM_DIR := vendor/Nim
 #- forces a rebuild of csources, Nimble and a complete compiler rebuild, in case we're called after pulling a new Nim version
 #- uses our Git submodules for csources and Nimble (Git doesn't let us place them in another submodule)
+#- build_all.sh looks at the parent dir to decide whether to copy the resulting csources binary there,
+#  but this is broken when using symlinks, so build csources separately (we get parallel compiling as a bonus)
+#- Windows is a special case, as usual
 #- recompiles Nimble with -d:release until we upgrade to nim-0.20 where koch does it by default
 #  (we don't actually use Nimble in this Makefile, but we need it in submodules to manually run tests: "../../env.sh nimble test")
+ifeq ($(OS), Windows_NT)
+  BUILD_CSOURCES := \
+    $(MAKE) myos=windows clean && \
+    $(MAKE) myos=windows CC=gcc LD=gcc
+else
+  BUILD_CSOURCES := \
+    $(MAKE) clean && \
+    $(MAKE) LD=$(CC)
+endif
 BUILD_NIM := cd $(NIM_DIR) && \
 	rm -rf bin/nim_csources csources dist/nimble && \
 	ln -sr ../Nim-csources csources && \
+	mkdir -p dist && \
 	ln -sr ../nimble dist/nimble && \
+	cd csources && \
+	$(BUILD_CSOURCES) && \
+	cd - && \
+	[ -e csources/bin ] && { \
+		cp -a csources/bin/nim bin/nim && \
+		cp -a csources/bin/nim bin/nim_csources && \
+		rm -rf csources/bin; \
+	} || { \
+		cp -a bin/nim bin/nim_csources; \
+	} && \
 	sh build_all.sh && \
 	$(ENV_SCRIPT) nim c -d:release --noNimblePath -p:compiler --nilseqs:on -o:bin/nimble dist/nimble/src/nimble.nim
 
@@ -69,7 +97,7 @@ $(NIMBLE_DIR): | $(NIM_DIR)/bin/nim
 	git submodule foreach --quiet '\
 		[ `ls -1 *.nimble 2>/dev/null | wc -l ` -gt 0 ] && { \
 			mkdir -p $$toplevel/$(NIMBLE_DIR)/pkgs/$${sm_path#*/}-#head;\
-			echo -e "$$(pwd)\n$$(pwd)" > $$toplevel/$(NIMBLE_DIR)/pkgs/$${sm_path#*/}-#head/$${sm_path#*/}.nimble-link;\
+			echo -e "$$($(PWD))\n$$($(PWD))" > $$toplevel/$(NIMBLE_DIR)/pkgs/$${sm_path#*/}-#head/$${sm_path#*/}.nimble-link;\
 		} || true'
 
 # builds and runs all tests
@@ -78,7 +106,7 @@ test: | build deps
 
 # usual cleaning
 clean:
-	rm -rf build/{nimbus,all_tests,beacon_node,validator_keygen,*.exe} $(NIMBLE_DIR)
+	rm -rf build/{nimbus,all_tests,beacon_node,validator_keygen,*.exe} $(NIMBLE_DIR) $(NIM_DIR)/bin/nim
 
 # dangerous cleaning, because you may have not-yet-pushed branches and commits in those vendor repos you're about to delete
 mrproper: clean
@@ -92,22 +120,22 @@ github-ssh:
 		;done
 
 #- re-builds the Nim compiler (not usually needed, because `make update` does it when necessary)
+#- allows parallel building with the '+' prefix
 build-nim: | deps
-	$(BUILD_NIM)
+	+ $(BUILD_NIM)
 
-#- inits and updates the Git submodules, making sure we're not left on a detached HEAD
+#- initialises and updates the Git submodules
 #- deletes the ".nimble" dir to force the execution of the "deps" target
-#- ignores non-zero exit codes from [...] tests
+#- allows parallel building with the '+' prefix
 #- TODO: rebuild the Nim compiler after the corresponding submodule is updated
 $(NIM_DIR)/bin/nim update:
-	git submodule update --init --recursive --rebase
-	git submodule foreach --recursive 'git checkout $$(git config -f $$toplevel/.gitmodules submodule.$$name.branch || echo master)'
+	git submodule update --init --recursive
 	rm -rf $(NIMBLE_DIR)
-	[ -e $(NIM_DIR)/bin/nim ] || { $(BUILD_NIM); }
+	+ [ -e $(NIM_DIR)/bin/nim ] || { $(BUILD_NIM); }
 
 # don't use this target, or you risk updating dependency repos that are not ready to be used in Nimbus
 update-remote:
-	git submodule update --remote --recursive --rebase
+	git submodule update --remote --rebase
 
 # runs `git status` in all Git repos
 status: | $(REPOS)
diff --git a/README.md b/README.md
index 156d1ecd0..f96cba735 100644
--- a/README.md
+++ b/README.md
@@ -59,6 +59,7 @@ make test
 
 To pull the latest changes in all the Git repositories involved:
 ```bash
+git pull
 make update
 ```
 
@@ -100,6 +101,59 @@ You can now follow those instructions in the previous section by replacing `make
 
 - the Premix debugging tools are [documented separately](premix/readme.md)
 
+#### Git submodule workflow
+
+Working on a dependency:
+
+```bash
+cd vendor/nim-chronicles
+git checkout -b mybranch
+# make some changes
+git status
+git commit -a
+git push origin mybranch
+# create a GitHub PR and wait for it to be approved and merged
+git checkout master
+git pull
+git branch -d mybranch
+# realise that the merge was done without "--no-ff"
+git branch -D mybranch
+# update the submodule's commit in the superproject
+cd ../..
+git status
+git add vendor/nim-chronicles
+git commit
+```
+
+It's important that you only update the submodule commit after it's available upstream.
+
+You might want to do this on a new branch of the superproject, so you can make
+a GitHub PR for it and see the CI test results.
+
+Don't update all Git submodules at once, just because you found the relevant
+Git command or `make` target. You risk updating submodules to other people's
+latest commits when they are not ready to be used in the superproject.
+
+Adding the submodule "https://github.com/status-im/foo" to "vendor/foo":
+
+```bash
+./add_submodule.sh status-im/foo
+```
+
+Removing the submodule "vendor/bar":
+
+```bash
+git submodule deinit -f -- vendor/bar
+git rm -f vendor/bar
+```
+
+Checking out older commits, either to bisect something or to reproduce an older build:
+
+```bash
+git checkout <commit hash here>
+make -j8 clean update
+```
+
 ### Troubleshooting
 
 Report any errors you encounter, please, if not [already documented](https://github.com/status-im/nimbus/issues)!
diff --git a/vendor/nim-asyncdispatch2 b/vendor/nim-asyncdispatch2
deleted file mode 160000
index 88933e8f1..000000000
--- a/vendor/nim-asyncdispatch2
+++ /dev/null
@@ -1 +0,0 @@
-Subproject commit 88933e8f1bd9fce513a9ea885d1859efd14386ee
diff --git a/vendor/nim-beacon-chain b/vendor/nim-beacon-chain
index 7f1bddb26..56a48cc60 160000
--- a/vendor/nim-beacon-chain
+++ b/vendor/nim-beacon-chain
@@ -1 +1 @@
-Subproject commit 7f1bddb267dd11d340675204854e2f2d30be2433
+Subproject commit 56a48cc60f1b1feeaadda4912dae9554ed51ae63
diff --git a/vendor/nim-blscurve b/vendor/nim-blscurve
index 13a89c9d7..1d41c83ca 160000
--- a/vendor/nim-blscurve
+++ b/vendor/nim-blscurve
@@ -1 +1 @@
-Subproject commit 13a89c9d73c7029b53a7a9dd7cededfd51348df7
+Subproject commit 1d41c83ca68e3422d2c54359d38d10fa103d43f9
diff --git a/vendor/nim-chronos b/vendor/nim-chronos
new file mode 160000
index 000000000..79376dab2
--- /dev/null
+++ b/vendor/nim-chronos
@@ -0,0 +1 @@
+Subproject commit 79376dab2044724a4bf527aa26e86afb42bb2ad8
diff --git a/vendor/nim-eth b/vendor/nim-eth
index 0bc80d73c..5f6155bd2 160000
--- a/vendor/nim-eth
+++ b/vendor/nim-eth
@@ -1 +1 @@
-Subproject commit 0bc80d73cdd973c24b5d10c86a74904373a944b9
+Subproject commit 5f6155bd235654ac25b37bb781ee2a6a671d2b7d
diff --git a/vendor/nim-json-rpc b/vendor/nim-json-rpc
index 1083b2972..53ed44dfa 160000
--- a/vendor/nim-json-rpc
+++ b/vendor/nim-json-rpc
@@ -1 +1 @@
-Subproject commit 1083b2972a183c4e1221f0ea3671dc7ad193f92d
+Subproject commit 53ed44dfa59f48ef8e3edfec2c78222458b6454a