diff --git a/README.adoc b/README.adoc
index 7380211..e93c666 100644
--- a/README.adoc
+++ b/README.adoc
@@ -110,6 +110,22 @@ Not all packages have an alias, when they don't, just use the form:
 ./build -- <pkg>-reconfigure
 ....
 
+=== Don't retype arguments all the time
+
+It gets annoying to retype `-a aarch64` for every single command, or to remember `./build -B` setups.
+
+So simplify that, do:
+
+....
+cp cli.gitignore.example cli.gitignore
+....
+
+and then edit the `cli.gitignore` file to your needs.
+
+That file is used to pass extra command line arguments to most of our utilities.
+
+Of course, you could get by with the shell history, or your own aliases, but we've felt that it was worth introducing a common mechanism for that.
+
 === Clean the build
 
 You did something crazy, and nothing seems to work anymore?
@@ -1231,12 +1247,52 @@ Inside QEMU:
 startx
 ....
 
+And then from the GUI you can start exciting graphical programs such as:
+
+....
+xcalc
+xeyes
+....
+
 image:x11.png[image]
 
 More details: https://unix.stackexchange.com/questions/70931/how-to-install-x11-on-my-own-linux-buildroot-system/306116#306116
 
 Not sure how well that graphics stack represents real systems, but if it does it would be a good way to understand how it works.
 
+=== X11 mouse not moving
+
+TODO 9076c1d9bcc13b6efdb8ef502274f846d8d4e6a1 I'm 100% sure that it was working before, but I didn't run it forever, and it stopped working at some point. Needs bisection, on whatever commit last touched x11 stuff.
+
+* https://askubuntu.com/questions/730891/how-can-i-get-a-mouse-cursor-in-qemu
+* https://stackoverflow.com/questions/19665412/mouse-and-keyboard-not-working-in-qemu-emulator
+
+`-show-cursor` did not help, I just get to see the host cursor, but the guest cursor still does not move.
+
+Doing:
+
+....
+watch -n 1 grep i8042 /proc/interrupts
+....
+
+shows that interrupts do happen when mouse and keyboard presses are done, so I expect that it is some wrong either with:
+
+* QEMU. Same behaviour if I try the host's QEMU 2.10.1 however.
+* X11 configuration. We do have `BR2_PACKAGE_XDRIVER_XF86_INPUT_MOUSE=y`.
+
+`/var/log/Xorg.0.log` contains the following interesting lines:
+
+....
+[    27.549] (II) LoadModule: "mouse"
+[    27.549] (II) Loading /usr/lib/xorg/modules/input/mouse_drv.so
+[    27.590] (EE) <default pointer>: Cannot find which device to use.
+[    27.590] (EE) <default pointer>: cannot open input device
+[    27.590] (EE) PreInit returned 2 for "<default pointer>"
+[    27.590] (II) UnloadModule: "mouse"
+....
+
+The file `/dev/inputs/mice` does not exist.
+
 === X11 ARM
 
 On ARM, `startx` hangs at a message:
@@ -2621,9 +2677,10 @@ External open source benchmarks. We will try to create Buildroot packages for th
 Buildroot supports it, which makes everything just trivial:
 
 ....
-printf 'BR2_PACKAGE_OPENBLAS=y\n' >> br2.gitignore
-printf 'BR2_TARGET_ROOTFS_EXT2_SIZE="128M"\n' >> br2.gitignore
-./build -a arm -g -b br2.gitignore -- kernel_module-reconfigure
+./build \
+  -a arm \
+  -B 'BR2_PACKAGE_OPENBLAS=y' \
+;
 ....
 
 and then inside the guest run our test program:
@@ -2635,7 +2692,7 @@ and then inside the guest run our test program:
 For x86, you also need:
 
 ....
-printf 'BR2_PACKAGE_OPENBLAS_TARGET="NEHALEM"\n' >> br2.gitignore
+-B 'BR2_PACKAGE_OPENBLAS_TARGET="NEHALEM"'
 ....
 
 to overcome this bug: https://bugs.busybox.net/show_bug.cgi?id=10856
@@ -2741,7 +2798,7 @@ If you still want to run this, try it out with:
 
 ....
 ./build \
-  -a arm \
+  -a aarch64 \
   -B 'BR2_PACKAGE_PARSEC_BENCHMARK=y' \
   -B 'BR2_PACKAGE_PARSEC_BENCHMARK_PARSECMGMT=y' \
   -B 'BR2_TARGET_ROOTFS_EXT2_SIZE="3G"' \
@@ -3398,12 +3455,7 @@ dmesg
 
 We provide the following mechanisms:
 
-* `./build -b br2.gitignore`: append the file `br2.gitignore` to a single build. Must be passed every time you run `./build`. A good template is provided by:
-+
-....
-cp br2.gitignore.example br2.gitignore
-....
-+
+* `./build -b mybr2.gitignore`: append the file `mybr2.gitignore` to a single build. Must be passed every time you run `./build`. A good template is provided by:
 * `./build -B 'BR2_SOM_OPTION="myval"'`: append a single option to a single build.
 
 === Find Buildroot options with make menuconfig
@@ -3563,8 +3615,22 @@ Our philosophy is:
 
 * if something adds little to the build time, build it in by default
 * otherwise, make it optional
-
-The build biggest time hog is always GCC, and it does not look like we can use a precompiled one: https://stackoverflow.com/questions/10833672/buildroot-environment-with-host-toolchain
+* try to keep the toolchain (GCC, Binutils) unchanged, otherwise a full rebuild is  required.
++
+So we generally just enable all toolchain options by defaut, even though this adds a bit of time to the build.
++
+The biggest build time hog is always GCC, and it does not look like we can use a precompiled one: https://stackoverflow.com/questions/10833672/buildroot-environment-with-host-toolchain
+* if something is very vaulable, we just add it by default even if it increases the Build time, notably GDB and QEMU
+* runtime is sacred.
++
+We do our best to reduce the instruction and feature count to the bare minimum needed, to make the system:
++
+--
+** easier to understand
+** run faster, specially for <<gem5>>
+--
++
+One possibility we could play with is to build loadable modules instead of built-in modules to reduce runtime, but make it easier to get started with the modules.
 
 === Benchmark machines
 
diff --git a/br2.gitignore.example b/br2.gitignore.example
deleted file mode 100644
index e924e85..0000000
--- a/br2.gitignore.example
+++ /dev/null
@@ -1,10 +0,0 @@
-#BR2_TARGET_ROOTFS_EXT2_SIZE="512M"
-
-#BR2_PACKAGE_OPENSSH=y
-
-#BR2_PACKAGE_OPENBLAS=y
-#BR2_PACKAGE_OPENBLAS_TARGET="NEHALEM"
-
-#BR2_PACKAGE_PARSEC_BENCHMARK=y
-#BR2_PACKAGE_PARSEC_BENCHMARK_BUILD_LIST="all"
-#BR2_PACKAGE_PARSEC_BENCHMARK_INPUT_SIZE="test"
diff --git a/build b/build
index a9b2d82..2b14372 100755
--- a/build
+++ b/build
@@ -1,83 +1,87 @@
 #!/usr/bin/env bash
 set -eu
 . common
+set -- ${cli_build:-} "$@"
 arch=x86_64
 rm -f br2_cli.gitignore
 touch br2_cli.gitignore
 configure=true
 config_fragments='br2'
-extra_make_args=''
+extra_make_args=
 gem5=false
 j="$(($(nproc) - 2))"
 linux_reconfigure=false
-linux_kernel_custom_config_file=''
-post_script_args=''
+linux_kernel_custom_config_file=
+post_script_args=
 qemu_sdl='--enable-sdl --with-sdlabi=2.0'
 v=0
 while getopts 'a:B:b:CGgj:hIiK:klp:qSv' OPT; do
   case "$OPT" in
     a)
       arch="$OPTARG"
-    ;;
+      ;;
     b)
       config_fragments="$config_fragments $OPTARG"
-    ;;
+      ;;
     B)
       echo "$OPTARG" >> br2_cli.gitignore
-    ;;
+      ;;
     C)
       configure=false
-    ;;
+      ;;
     G)
       extra_make_args="$extra_make_args gem5-reconfigure"
       gem5=true
-    ;;
+      ;;
     g)
       gem5=true
-    ;;
+      ;;
     h)
       cat build-usage.adoc 1>&2
       exit
-    ;;
+      ;;
     I)
       echo "
 BR2_TARGET_ROOTFS_CPIO=n
 BR2_TARGET_ROOTFS_EXT2=n
 BR2_TARGET_ROOTFS_INITRAMFS=y
 " >> br2_cli.gitignore
-    ;;
+      ;;
     i)
       echo "
 BR2_TARGET_ROOTFS_CPIO=y
 BR2_TARGET_ROOTFS_EXT2=n
 BR2_TARGET_ROOTFS_INITRAMFS=n
 " >> br2_cli.gitignore
-    ;;
+      ;;
     j)
       echo "$OPTARG" >> br2_cli.gitignore
-    ;;
+      ;;
     K)
       linux_kernel_custom_config_file="$OPTARG"
-    ;;
+      ;;
     k)
       extra_make_args="$extra_make_args kernel_module-reconfigure"
-    ;;
+      ;;
     l)
       linux_reconfigure=true
       extra_make_args="$extra_make_args linux-reconfigure"
-    ;;
+      ;;
     p)
       post_script_args="$OPTARG"
-    ;;
+      ;;
     q)
       extra_make_args="$extra_make_args host-qemu-reconfigure"
-    ;;
+      ;;
     S)
-      qemu_sdl=''
-    ;;
+      qemu_sdl=
+      ;;
     v)
       v=1
-    ;;
+      ;;
+    ?)
+      exit 2
+      ;;
   esac
 done
 shift $(($OPTIND - 1))
diff --git a/cli.gitignore.example b/cli.gitignore.example
new file mode 100644
index 0000000..bfcddae
--- /dev/null
+++ b/cli.gitignore.example
@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+arch=x86_64
+gem5=
+#gem5=-g
+printf '
+#BR2_TARGET_ROOTFS_EXT2_SIZE="1024M"
+' > br2.gitignore
+cli_build="-a ${arch} -b br2.gitignore -b br2_x11 ${gem5}"
+cli_run="-a ${arch} ${gem5}"
+cli_rungdb="-a ${arch} ${gem5}"
+cli_rungdbserver="-a ${arch} ${gem5}"
+cli_rungdb_user="-a ${arch} ${gem5}"
+cli_trace_boot="-a ${arch}"
+cli_trace2line="-a ${arch}"
diff --git a/common b/common
index 54c8a2e..141be97 100644
--- a/common
+++ b/common
@@ -17,3 +17,7 @@ set_common_vars() {
   qemu_out_dir="${out_arch_dir}/qemu"
   common_dir="${out_dir}/common"
 }
+f=cli.gitignore
+if [ -f "$f" ]; then
+  . "$f"
+fi
diff --git a/configure b/configure
index ab369de..e6178ab 100755
--- a/configure
+++ b/configure
@@ -4,7 +4,7 @@ interactive_pkgs=libsdl2-dev
 gem5=false
 qemu=true
 submodules='buildroot linux'
-y=''
+y=
 while getopts gpqt OPT; do
   case "$OPT" in
     g)
@@ -17,7 +17,7 @@ while getopts gpqt OPT; do
       qemu=false
       ;;
     t)
-      interactive_pkgs=''
+      interactive_pkgs=
       y='-y'
       ;;
   esac
diff --git a/gem5/build b/gem5/build
index 3d6b3b8..04c0db8 100755
--- a/gem5/build
+++ b/gem5/build
@@ -1,8 +1,8 @@
 #/usr/bin/env bash
 set -eu
 arch=x86_64
-cross_compile=''
-j=''
+cross_compile=
+j=
 while getopts a:c:j: OPT; do
   case "$OPT" in
     a)
diff --git a/parsec-benchmark/Config.in b/parsec-benchmark/Config.in
index 8eae05b..65495af 100644
--- a/parsec-benchmark/Config.in
+++ b/parsec-benchmark/Config.in
@@ -28,6 +28,8 @@ config BR2_PACKAGE_PARSEC_BENCHMARK_PARSECMGMT
 	  The other option would be to patch Parsec to use /bin/sh and be POSIX compliant.
 	  But let's take the path of smallest resistance for now.
 
+if !BR2_PACKAGE_PARSEC_BENCHMARK_PARSECMGMT
+
 config BR2_PACKAGE_PARSEC_BENCHMARK_INPUT_SIZE
 	string "input_size"
 	default test
@@ -35,3 +37,5 @@ config BR2_PACKAGE_PARSEC_BENCHMARK_INPUT_SIZE
 	  Which input size to generate on the host for the guest.
 
 endif
+
+endif
diff --git a/run b/run
index 0733a6e..e46369e 100755
--- a/run
+++ b/run
@@ -1,11 +1,12 @@
 #!/usr/bin/env bash
 set -eu
 . common
+set -- ${cli_run:-} "$@"
 
 # CLI handling.
 arch=x86_64
 cpus=1
-debug_vm=''
+debug_vm=
 debug=false
 kgdb=false
 kvm=false
@@ -14,18 +15,20 @@ kvm=false
 # nokaslr: https://unix.stackexchange.com/questions/397939/turning-off-kaslr-to-debug-linux-kernel-using-qemu-and-gdb
 #   Turned on by default since v4.12
 extra_append='nokaslr norandmaps printk.devkmsg=on printk.time=y'
-extra_append_after_dash=''
-extra_flags=''
-extra_flags_qemu=''
+extra_append_after_dash=
+extra_flags=
+extra_flags_qemu=
 gem5=false
-gem5opts=''
-lkmc_eval=''
+gem5opts=
+lkmc_eval=
 initrd=false
 initramfs=false
 memory=256M
 nographic=true
-root=''
-trace_enable=''
+root=
+# A dummy value that is already turned on by default and does not produce large output,
+# just to prevent QEMU from emitting a warning that '' is not valid.
+trace_enable=pr_manager_run
 while getopts a:c:DdE:e:f:G:ghIiKkm:T:x OPT; do
   case "$OPT" in
     a)
@@ -59,7 +62,7 @@ while getopts a:c:DdE:e:f:G:ghIiKkm:T:x OPT; do
     h)
       cat build-usage.adoc 1>&2
       exit
-    ;;
+      ;;
     I)
       initramfs=true
       ;;
@@ -85,6 +88,9 @@ while getopts a:c:DdE:e:f:G:ghIiKkm:T:x OPT; do
     x)
       nographic=false
       ;;
+    ?)
+      exit 2
+      ;;
   esac
 done
 shift "$(($OPTIND - 1))"
diff --git a/rungdb b/rungdb
index b30fa30..a00336a 100755
--- a/rungdb
+++ b/rungdb
@@ -1,20 +1,21 @@
 #!/usr/bin/env bash
 set -eu
 . common
-after=''
+set -- ${cli_rungdb:-} "$@"
+after=
 arch='x86_64'
-before=''
+before=
 gem5=false
 lx_symbols="-ex 'lx-symbols ../kernel_module-1.0/'"
 kgdb=false
 while getopts A:a:b:gkL OPT; do
   case "$OPT" in
-    a)
-      arch="$OPTARG"
-      ;;
     A)
       after="$OPTARG"
       ;;
+    a)
+      arch="$OPTARG"
+      ;;
     b)
       before="$OPTARG"
       ;;
@@ -25,7 +26,10 @@ while getopts A:a:b:gkL OPT; do
       kgdb=true
       ;;
     L)
-      lx_symbols=''
+      lx_symbols=
+      ;;
+    ?)
+      exit 2
       ;;
   esac
 done
@@ -34,7 +38,7 @@ if [ "$#" -gt 0 ]; then
   brk="-ex 'break ${1}'"
   shift
 else
-  brk=''
+  brk=
 fi
 if "$gem5"; then
   port=7000
diff --git a/rungdb-user b/rungdb-user
index af439d3..cb0db5d 100755
--- a/rungdb-user
+++ b/rungdb-user
@@ -1,10 +1,11 @@
 #!/usr/bin/env bash
 set -eu
 . common
+set -- ${cli_rungdb_user:-} "$@"
 usage="$0 <exec-relative-path> [<brk-symbol>]"
 arch='x86_64'
 gem5=false
-gem5_opt=''
+gem5_opt=
 while getopts a:gh OPT; do
   case "$OPT" in
     a)
@@ -18,6 +19,9 @@ while getopts a:gh OPT; do
       echo "$usage"
       exit 0
       ;;
+    ?)
+      exit 2
+      ;;
   esac
 done
 shift "$(($OPTIND - 1))"
@@ -27,7 +31,7 @@ if [ "$#" -gt 0 ]; then
   brk="'$1'"
   shift
 else
-  brk=''
+  brk=
 fi
 set_common_vars "$arch" "$gem5"
 executable="${build_dir}/${executable_rel}"
diff --git a/rungdbserver b/rungdbserver
index 1ddc9d0..f6f3e32 100755
--- a/rungdbserver
+++ b/rungdbserver
@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 set -eu
 . common
+set -- ${cli_rungdbserver:-} "$@"
 arch='x86_64'
 gem5=false
 while getopts a:g OPT; do
diff --git a/trace-boot b/trace-boot
index 76973b1..a16f411 100755
--- a/trace-boot
+++ b/trace-boot
@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 set -eu
 . common
+set -- ${cli_trace_boot:-} "$@"
 arch=x86_64
 while getopts a: OPT; do
   case "$OPT" in
diff --git a/trace2line b/trace2line
index f145cdf..04f6c30 100755
--- a/trace2line
+++ b/trace2line
@@ -1,6 +1,7 @@
 #!/usr/bin/env bash
 set -eu
 . common
+set -- ${cli_trace2line:-} "$@"
 arch=x86_64
 while getopts a: OPT; do
   case "$OPT" in