diff --git a/MozillaFirefox.changes b/MozillaFirefox.changes
index 7dccc75..d0b800b 100644
--- a/MozillaFirefox.changes
+++ b/MozillaFirefox.changes
@@ -1,3 +1,9 @@
+-------------------------------------------------------------------
+Thu Sep 17 11:45:31 UTC 2020 - Guillaume GARDET <guillaume.gardet@opensuse.org>
+
+- Use %limit_build macro again for aarch64 and armv7, instead of 
+  the new memoryperjob _constraints to use more workers
+
 -------------------------------------------------------------------
 Sat Aug 22 06:52:01 UTC 2020 - Wolfgang Rosenauer <wr@rosenauer.org>
 
diff --git a/MozillaFirefox.spec b/MozillaFirefox.spec
index 1d301c3..72c121f 100644
--- a/MozillaFirefox.spec
+++ b/MozillaFirefox.spec
@@ -82,6 +82,7 @@ BuildRequires:  autoconf213
 BuildRequires:  dbus-1-glib-devel
 BuildRequires:  dejavu-fonts
 BuildRequires:  fdupes
+BuildRequires:  memory-constraints
 %if 0%{?suse_version} <= 1320
 BuildRequires:  gcc9-c++
 %else
@@ -431,6 +432,9 @@ echo "export MOZ_TELEMETRY_REPORTING=1"
 echo ""
 cat << EOF
 %else
+%ifarch aarch64 %arm
+%limit_build -m 2000
+%endif
 cat << EOF > $MOZCONFIG
 %endif
 mk_add_options MOZILLA_OFFICIAL=1
diff --git a/_constraints b/_constraints
index 8c6fedd..b0130e5 100644
--- a/_constraints
+++ b/_constraints
@@ -17,12 +17,15 @@
       <arch>armv7l</arch>
     </conditions>
     <hardware>
+      <memoryperjob>
+        <size unit="M">1000</size>
+      </memoryperjob>
       <disk>
         <size unit="G">12</size>
       </disk>
-      <memory>
+      <physicalmemory>
         <size unit="G">5</size>
-      </memory>
+      </physicalmemory>
     </hardware>
   </overwrite>
   <overwrite>
@@ -30,9 +33,13 @@
       <arch>aarch64</arch>
     </conditions>
     <hardware>
-      <memory>
+      <processors>4</processors>
+      <memoryperjob>
+        <size unit="M">1000</size>
+      </memoryperjob>
+      <physicalmemory>
         <size unit="G">12</size>
-      </memory>
+      </physicalmemory>
     </hardware>
   </overwrite>
   <overwrite>