Diff of the two buildlogs:

--
--- b1/build.log	2025-01-24 02:37:09.642194860 +0000
+++ b2/build.log	2025-01-24 02:57:36.362734584 +0000
@@ -1,6 +1,6 @@
 I: pbuilder: network access will be disabled during build
-I: Current time: Thu Jan 23 14:23:24 -12 2025
-I: pbuilder-time-stamp: 1737685404
+I: Current time: Fri Jan 24 16:37:28 +14 2025
+I: pbuilder-time-stamp: 1737686248
 I: Building the build Environment
 I: extracting base tarball [/var/cache/pbuilder/unstable-reproducible-base.tgz]
 I: copying local configuration
@@ -22,52 +22,84 @@
 dpkg-source: info: unpacking haskell-copilot-core_4.2-1.debian.tar.xz
 I: using fakeroot in build.
 I: Installing the build-deps
-I: user script /srv/workspace/pbuilder/11721/tmp/hooks/D02_print_environment starting
+I: user script /srv/workspace/pbuilder/31400/tmp/hooks/D01_modify_environment starting
+debug: Running on wbq0.
+I: Changing host+domainname to test build reproducibility
+I: Adding a custom variable just for the fun of it...
+I: Changing /bin/sh to bash
+'/bin/sh' -> '/bin/bash'
+lrwxrwxrwx 1 root root 9 Jan 24 02:38 /bin/sh -> /bin/bash
+I: Setting pbuilder2's login shell to /bin/bash
+I: Setting pbuilder2's GECOS to second user,second room,second work-phone,second home-phone,second other
+I: user script /srv/workspace/pbuilder/31400/tmp/hooks/D01_modify_environment finished
+I: user script /srv/workspace/pbuilder/31400/tmp/hooks/D02_print_environment starting
 I: set
-  BUILDDIR='/build/reproducible-path'
-  BUILDUSERGECOS='first user,first room,first work-phone,first home-phone,first other'
-  BUILDUSERNAME='pbuilder1'
-  BUILD_ARCH='armhf'
-  DEBIAN_FRONTEND='noninteractive'
-  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=3 '
-  DISTRIBUTION='unstable'
-  HOME='/root'
-  HOST_ARCH='armhf'
+  BASH=/bin/sh
+  BASHOPTS=checkwinsize:cmdhist:complete_fullquote:extquote:force_fignore:globasciiranges:globskipdots:hostcomplete:interactive_comments:patsub_replacement:progcomp:promptvars:sourcepath
+  BASH_ALIASES=()
+  BASH_ARGC=()
+  BASH_ARGV=()
+  BASH_CMDS=()
+  BASH_LINENO=([0]="12" [1]="0")
+  BASH_LOADABLES_PATH=/usr/local/lib/bash:/usr/lib/bash:/opt/local/lib/bash:/usr/pkg/lib/bash:/opt/pkg/lib/bash:.
+  BASH_SOURCE=([0]="/tmp/hooks/D02_print_environment" [1]="/tmp/hooks/D02_print_environment")
+  BASH_VERSINFO=([0]="5" [1]="2" [2]="37" [3]="1" [4]="release" [5]="arm-unknown-linux-gnueabihf")
+  BASH_VERSION='5.2.37(1)-release'
+  BUILDDIR=/build/reproducible-path
+  BUILDUSERGECOS='second user,second room,second work-phone,second home-phone,second other'
+  BUILDUSERNAME=pbuilder2
+  BUILD_ARCH=armhf
+  DEBIAN_FRONTEND=noninteractive
+  DEB_BUILD_OPTIONS='buildinfo=+all reproducible=+all parallel=4 '
+  DIRSTACK=()
+  DISTRIBUTION=unstable
+  EUID=0
+  FUNCNAME=([0]="Echo" [1]="main")
+  GROUPS=()
+  HOME=/root
+  HOSTNAME=i-capture-the-hostname
+  HOSTTYPE=arm
+  HOST_ARCH=armhf
   IFS=' 	
   '
-  INVOCATION_ID='106f824e8b464f5e8ee9712f8c30f0f9'
-  LANG='C'
-  LANGUAGE='en_US:en'
-  LC_ALL='C'
-  MAIL='/var/mail/root'
-  OPTIND='1'
-  PATH='/usr/sbin:/usr/bin:/sbin:/bin:/usr/games'
-  PBCURRENTCOMMANDLINEOPERATION='build'
-  PBUILDER_OPERATION='build'
-  PBUILDER_PKGDATADIR='/usr/share/pbuilder'
-  PBUILDER_PKGLIBDIR='/usr/lib/pbuilder'
-  PBUILDER_SYSCONFDIR='/etc'
-  PPID='11721'
-  PS1='# '
-  PS2='> '
+  INVOCATION_ID=c6d6001078a6482ba8c8c363dffafa5f
+  LANG=C
+  LANGUAGE=it_CH:it
+  LC_ALL=C
+  MACHTYPE=arm-unknown-linux-gnueabihf
+  MAIL=/var/mail/root
+  OPTERR=1
+  OPTIND=1
+  OSTYPE=linux-gnueabihf
+  PATH=/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path
+  PBCURRENTCOMMANDLINEOPERATION=build
+  PBUILDER_OPERATION=build
+  PBUILDER_PKGDATADIR=/usr/share/pbuilder
+  PBUILDER_PKGLIBDIR=/usr/lib/pbuilder
+  PBUILDER_SYSCONFDIR=/etc
+  PIPESTATUS=([0]="0")
+  POSIXLY_CORRECT=y
+  PPID=31400
   PS4='+ '
-  PWD='/'
-  SHELL='/bin/bash'
-  SHLVL='2'
-  SUDO_COMMAND='/usr/bin/timeout -k 18.1h 18h /usr/bin/ionice -c 3 /usr/bin/nice /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.mXl9NPZ7/pbuilderrc_UvwO --distribution unstable --hookdir /etc/pbuilder/first-build-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/unstable-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.mXl9NPZ7/b1 --logfile b1/build.log haskell-copilot-core_4.2-1.dsc'
-  SUDO_GID='113'
-  SUDO_UID='107'
-  SUDO_USER='jenkins'
-  TERM='unknown'
-  TZ='/usr/share/zoneinfo/Etc/GMT+12'
-  USER='root'
-  _='/usr/bin/systemd-run'
-  http_proxy='http://10.0.0.15:3142/'
+  PWD=/
+  SHELL=/bin/bash
+  SHELLOPTS=braceexpand:errexit:hashall:interactive-comments:posix
+  SHLVL=3
+  SUDO_COMMAND='/usr/bin/timeout -k 24.1h 24h /usr/bin/ionice -c 3 /usr/bin/nice -n 11 /usr/bin/unshare --uts -- /usr/sbin/pbuilder --build --configfile /srv/reproducible-results/rbuild-debian/r-b-build.mXl9NPZ7/pbuilderrc_QSGp --distribution unstable --hookdir /etc/pbuilder/rebuild-hooks --debbuildopts -b --basetgz /var/cache/pbuilder/unstable-reproducible-base.tgz --buildresult /srv/reproducible-results/rbuild-debian/r-b-build.mXl9NPZ7/b2 --logfile b2/build.log haskell-copilot-core_4.2-1.dsc'
+  SUDO_GID=113
+  SUDO_UID=107
+  SUDO_USER=jenkins
+  TERM=unknown
+  TZ=/usr/share/zoneinfo/Etc/GMT-14
+  UID=0
+  USER=root
+  _='I: set'
+  http_proxy=http://10.0.0.15:3142/
 I: uname -a
-  Linux virt64c 6.1.0-30-arm64 #1 SMP Debian 6.1.124-1 (2025-01-12) aarch64 GNU/Linux
+  Linux i-capture-the-hostname 6.1.0-30-armmp #1 SMP Debian 6.1.124-1 (2025-01-12) armv7l GNU/Linux
 I: ls -l /bin
   lrwxrwxrwx 1 root root 7 Nov 22 14:40 /bin -> usr/bin
-I: user script /srv/workspace/pbuilder/11721/tmp/hooks/D02_print_environment finished
+I: user script /srv/workspace/pbuilder/31400/tmp/hooks/D02_print_environment finished
  -> Attempting to satisfy build-dependencies
  -> Creating pbuilder-satisfydepends-dummy package
 Package: pbuilder-satisfydepends-dummy
@@ -289,7 +321,7 @@
 Get: 153 http://deb.debian.org/debian unstable/main armhf libghc-test-framework-hunit-prof armhf 0.3.0.2-10 [22.8 kB]
 Get: 154 http://deb.debian.org/debian unstable/main armhf libghc-test-framework-quickcheck2-dev armhf 0.3.0.5-7 [30.6 kB]
 Get: 155 http://deb.debian.org/debian unstable/main armhf libghc-test-framework-quickcheck2-prof armhf 0.3.0.5-7 [28.5 kB]
-Fetched 308 MB in 7s (43.1 MB/s)
+Fetched 308 MB in 51s (6083 kB/s)
 Preconfiguring packages ...
 Selecting previously unselected package libedit2:armhf.
 (Reading database ... 
(Reading database ... 5%
(Reading database ... 10%
(Reading database ... 15%
(Reading database ... 20%
(Reading database ... 25%
(Reading database ... 30%
(Reading database ... 35%
(Reading database ... 40%
(Reading database ... 45%
(Reading database ... 50%
(Reading database ... 55%
(Reading database ... 60%
(Reading database ... 65%
(Reading database ... 70%
(Reading database ... 75%
(Reading database ... 80%
(Reading database ... 85%
(Reading database ... 90%
(Reading database ... 95%
(Reading database ... 100%
(Reading database ... 19557 files and directories currently installed.)
@@ -795,8 +827,8 @@
 Setting up tzdata (2025a-1) ...
 
 Current default time zone: 'Etc/UTC'
-Local time is now:      Fri Jan 24 02:26:51 UTC 2025.
-Universal Time is now:  Fri Jan 24 02:26:51 UTC 2025.
+Local time is now:      Fri Jan 24 02:45:16 UTC 2025.
+Universal Time is now:  Fri Jan 24 02:45:16 UTC 2025.
 Run 'dpkg-reconfigure tzdata' if you wish to change it.
 
 Setting up autotools-dev (20220109.1) ...
@@ -944,7 +976,11 @@
 fakeroot is already the newest version (1.36.2-1).
 0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
 I: Building the package
-I: Running cd /build/reproducible-path/haskell-copilot-core-4.2/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games" HOME="/nonexistent/first-build" dpkg-genchanges -S  > ../haskell-copilot-core_4.2-1_source.changes
+I: user script /srv/workspace/pbuilder/31400/tmp/hooks/A99_set_merged_usr starting
+Not re-configuring usrmerge for unstable
+I: user script /srv/workspace/pbuilder/31400/tmp/hooks/A99_set_merged_usr finished
+hostname: Name or service not known
+I: Running cd /build/reproducible-path/haskell-copilot-core-4.2/ && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-buildpackage -us -uc -b && env PATH="/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/i/capture/the/path" HOME="/nonexistent/second-build" dpkg-genchanges -S  > ../haskell-copilot-core_4.2-1_source.changes
 dpkg-buildpackage: info: source package haskell-copilot-core
 dpkg-buildpackage: info: source version 4.2-1
 dpkg-buildpackage: info: source distribution unstable
@@ -985,7 +1021,7 @@
 [2 of 2] Linking debian/hlibrary.setup
 perl -d:Confess -MDebian::Debhelper::Buildsystem::Haskell::Recipes=/.*/ \
 	-E 'configure_recipe'
-Running find . ! -newer /tmp/DW_mUpL9Tu -exec touch -d 1998-01-01 UTC {} ;
+Running find . ! -newer /tmp/fFV3q9nJr7 -exec touch -d 1998-01-01 UTC {} ;
 Running dh_listpackages
 libghc-copilot-core-dev
 libghc-copilot-core-prof
@@ -1271,8 +1307,8 @@
 Copilot.Core.Type:
   simpleType preserves inequality: [OK, passed 100 tests]
   reflexivity of equality of simple types: [OK, passed 100 tests]
-  symmetry of equality of simple types: [Arguments exhausted after 92 tests]
-  transitivity of equality of simple types: [Arguments exhausted after 3 tests]
+  symmetry of equality of simple types: [Arguments exhausted after 78 tests]
+  transitivity of equality of simple types: [Arguments exhausted after 7 tests]
   uniqueness of equality of simple types: [OK, passed 100 tests]
   typeLength matches array size for 1-dimensional arrays: [OK, passed 1 tests]
   typeLength matches array size for 2-dimensional arrays: [OK, passed 1 tests]
@@ -1335,7 +1371,7 @@
 creating dist-ghc/doc
 creating dist-ghc/doc/html
 creating dist-ghc/doc/html/copilot-core
-Running: /usr/bin/haddock '@dist-ghc/doc/html/copilot-core/haddock-response16007-1.txt' '--mathjax=file:///usr/share/javascript/mathjax/MathJax.js'
+Running: /usr/bin/haddock '@dist-ghc/doc/html/copilot-core/haddock-response3445-1.txt' '--mathjax=file:///usr/share/javascript/mathjax/MathJax.js'
  100% (  5 /  5) in 'Copilot.Core.Type.Array'
 Warning: 'Struct' is ambiguous. It is defined
     * at src/Copilot/Core/Type.hs:156:3
@@ -1704,7 +1740,7 @@
 dh_installdeb -plibghc-copilot-core-dev 
 dh_perl -plibghc-copilot-core-dev 
 dh_shlibdeps -plibghc-copilot-core-dev -- --ignore-missing-info
-dpkg-shlibdeps: warning: debian/libghc-copilot-core-dev/usr/lib/haskell-packages/ghc/lib/arm-linux-ghc-9.6.6/libHScopilot-core-4.2-DeCNcwvwIxA2gHts3DQGnp-ghc9.6.6.so contains an unresolvable reference to symbol stg_upd_frame_info: it's probably a plugin
+dpkg-shlibdeps: warning: debian/libghc-copilot-core-dev/usr/lib/haskell-packages/ghc/lib/arm-linux-ghc-9.6.6/libHScopilot-core-4.2-DeCNcwvwIxA2gHts3DQGnp-ghc9.6.6.so contains an unresolvable reference to symbol stg_ap_0_fast: it's probably a plugin
 dpkg-shlibdeps: warning: 17 other similar warnings have been skipped (use -v to see them all)
 dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/libghc-copilot-core-dev/usr/lib/haskell-packages/ghc/lib/arm-linux-ghc-9.6.6/libHScopilot-core-4.2-DeCNcwvwIxA2gHts3DQGnp-ghc9.6.6.so was not linked against libm.so.6 (it uses none of the library's symbols)
 dpkg-shlibdeps: warning: package could avoid a useless dependency if debian/libghc-copilot-core-dev/usr/lib/haskell-packages/ghc/lib/arm-linux-ghc-9.6.6/libHScopilot-core-4.2-DeCNcwvwIxA2gHts3DQGnp-ghc9.6.6.so was not linked against libgmp.so.10 (it uses none of the library's symbols)
@@ -1745,12 +1781,14 @@
 dpkg-buildpackage: info: binary-only upload (no source included)
 dpkg-genchanges: info: including full source code in upload
 I: copying local configuration
+I: user script /srv/workspace/pbuilder/31400/tmp/hooks/B01_cleanup starting
+I: user script /srv/workspace/pbuilder/31400/tmp/hooks/B01_cleanup finished
 I: unmounting dev/ptmx filesystem
 I: unmounting dev/pts filesystem
 I: unmounting dev/shm filesystem
 I: unmounting proc filesystem
 I: unmounting sys filesystem
 I: cleaning the build env 
-I: removing directory /srv/workspace/pbuilder/11721 and its subdirectories
-I: Current time: Thu Jan 23 14:37:03 -12 2025
-I: pbuilder-time-stamp: 1737686223
+I: removing directory /srv/workspace/pbuilder/31400 and its subdirectories
+I: Current time: Fri Jan 24 16:57:31 +14 2025
+I: pbuilder-time-stamp: 1737687451