diff --git a/pkgs/additional/koreader-from-src/debug.patch b/pkgs/additional/koreader-from-src/debug.patch
new file mode 100644
index 00000000..4f9f5531
--- /dev/null
+++ b/pkgs/additional/koreader-from-src/debug.patch
@@ -0,0 +1,13 @@
+diff --git a/base/thirdparty/cmake_modules/koreader_thirdparty_git.cmake b/base/thirdparty/cmake_modules/koreader_thirdparty_git.cmake
+index d8f9207a..32bee97c 100644
+--- a/base/thirdparty/cmake_modules/koreader_thirdparty_git.cmake
++++ b/base/thirdparty/cmake_modules/koreader_thirdparty_git.cmake
+@@ -24,6 +24,8 @@ endif()
+ 
+ set(run 0)
+ 
++message(STATUS \"ko_write_gitclone_script: checking '${gitclone_infofile}' against '${gitclone_stampfile}'\")
++
+ if(\"${gitclone_infofile}\" IS_NEWER_THAN \"${gitclone_stampfile}\")
+   set(run 1)
+ endif()
diff --git a/pkgs/additional/koreader-from-src/default.nix b/pkgs/additional/koreader-from-src/default.nix
index 76c4bd59..7579d88b 100644
--- a/pkgs/additional/koreader-from-src/default.nix
+++ b/pkgs/additional/koreader-from-src/default.nix
@@ -52,6 +52,9 @@ stdenv.mkDerivation rec {
   );
 
   patches = [
+    ./debug.patch
+    ./mupdf_dir.patch  #< TODO: needed?
+    ./mupdf_no_rm_build_dir.patch
     (substituteAll (
       {
         src = ./vendor-external-projects.patch;
@@ -112,12 +115,15 @@ stdenv.mkDerivation rec {
       # koreader will know to skip the `git clone` and `git checkout` calls.
       # the logic we're spoofing lives in koreader/base/thirdparty/cmake_modules/koreader_thirdparty_git.cmake
       stamp_dir="base/thirdparty/$lib/build/$platform/git_checkout/stamp"
-      echo "creating stamp in $stamp_dir for rev $rev"
+      stamp_info="$stamp_dir/$lib-gitinfo-$rev.txt"
+      stamp_clone="$stamp_dir/$lib-gitclone-lastrun.txt"
+      echo "creating stamps for $lib: $stamp_clone > $stamp_info"
       # mkdir $(dirname ..) to handle the case where `$rev` contains slashes
-      mkdir -p $(dirname "$stamp_dir/$lib-gitinfo-$rev.txt")
+      mkdir -p $(dirname "$stamp_info")
       # koreader-base decides whether to redo the git checkout based on a timestamp compare of these two stamp files
-      touch -d "last week" "$stamp_dir/$lib-gitinfo-$rev.txt"
-      touch -d "next week" "$stamp_dir/$lib-gitclone-lastrun.txt"
+      touch -d "last week" $(dirname "$stamp_info")  #< XXX: necessary?
+      touch -d "last week" "$stamp_info"
+      touch -d "next week" "$stamp_clone"
 
       # koreader would copy the checkout into this build/working directory,
       # but because we spoof the stamps to work around other git errors,
diff --git a/pkgs/additional/koreader-from-src/mupdf_dir.patch b/pkgs/additional/koreader-from-src/mupdf_dir.patch
new file mode 100644
index 00000000..7f93d9e5
--- /dev/null
+++ b/pkgs/additional/koreader-from-src/mupdf_dir.patch
@@ -0,0 +1,15 @@
+diff --git a/base/Makefile.defs b/base/Makefile.defs
+index dbb95daa..1293e5d5 100644
+--- a/base/Makefile.defs
++++ b/base/Makefile.defs
+@@ -732,8 +732,8 @@ MINIZIP_DIR=$(CURDIR)/$(MINIZIP_BUILD_DIR)/minizip-prefix/src/minizip
+ AES_LIB_DIR=$(MINIZIP_DIR)/aes
+ AES_LIB=$(MINIZIP_DIR)/libaes.a
+ 
+-MUPDF_BUILD_DIR=$(CURDIR)/$(THIRDPARTY_DIR)/mupdf/build/$(MACHINE)
+-MUPDF_DIR=$(MUPDF_BUILD_DIR)/mupdf-prefix/src/mupdf
++MUPDF_BUILD_DIR=$(THIRDPARTY_DIR)/mupdf/build/$(MACHINE)
++MUPDF_DIR=$(CURDIR)/$(MUPDF_BUILD_DIR)/mupdf-prefix/src/mupdf
+ MUPDF_LIB_DIR=$(MUPDF_DIR)/build/$(if $(KODEBUG),debug,release)
+ MUPDF_LIB_STATIC=$(MUPDF_LIB_DIR)/libmupdf.a
+ MUPDF_THIRDPARTY_LIBS=$(MUPDF_LIB_DIR)/libmupdfthird.a \
diff --git a/pkgs/additional/koreader-from-src/mupdf_no_rm_build_dir.patch b/pkgs/additional/koreader-from-src/mupdf_no_rm_build_dir.patch
new file mode 100644
index 00000000..083a9412
--- /dev/null
+++ b/pkgs/additional/koreader-from-src/mupdf_no_rm_build_dir.patch
@@ -0,0 +1,12 @@
+diff --git a/base/Makefile.third b/base/Makefile.third
+index f6a80523..061d2340 100644
+--- a/base/Makefile.third
++++ b/base/Makefile.third
+@@ -137,7 +137,6 @@ $(MUPDF_LIB) $(MUPDF_DIR)/include: $(JPEG_LIB) \
+ 		$(HARFBUZZ_LIB) $(HARFBUZZ_DIR)/include \
+ 		$(LIBWEBP_LIB) $(LIBWEBP_DIR)/include \
+ 		$(ZLIB) $(AES_LIB) $(THIRDPARTY_DIR)/mupdf/*.*
+-	-rm -rf $(MUPDF_BUILD_DIR)
+ 	install -d $(MUPDF_BUILD_DIR)
+ 	cd $(MUPDF_BUILD_DIR) && \
+ 		$(CMAKE) $(CMAKE_FLAGS) \
diff --git a/pkgs/additional/koreader-from-src/sources.nix b/pkgs/additional/koreader-from-src/sources.nix
index 0dba71e8..66cb4029 100644
--- a/pkgs/additional/koreader-from-src/sources.nix
+++ b/pkgs/additional/koreader-from-src/sources.nix
@@ -148,6 +148,7 @@
       source.hash = "sha256-P/3MMMGYDqD9NmkYvw/thKpUNa3wNOSlBBjANHSonAg=";
     };
     mupdf = {
+      # Completed
       source.url = "https://github.com/ArtifexSoftware/mupdf.git";
       source.rev = "tags/1.13.0";
       source.hash = "sha256-pQejRon9fO9A1mhz3oLjBr1j4HveDLcQIWjR1/Rpy5Q=";