diff '--color=auto' -urP loop-AES-v3.8e-build-initrd_prefer-l-a-losetup/build-initrd.sh loop-AES-v3.8e-build-initrd_initfstype/build-initrd.sh
--- loop-AES-v3.8e-build-initrd_prefer-l-a-losetup/build-initrd.sh	2024-10-11 12:24:11.542170501 -0600
+++ loop-AES-v3.8e-build-initrd_initfstype/build-initrd.sh	2024-10-11 15:31:36.719228138 -0600
@@ -74,6 +74,8 @@
 #  2.4 and older kernels always install to block/ directory
 #  2.6 kernels with loop-AES-v3.2a and later install to extra/ directory
 #
+# Note, if INITFSTYPE= is not minix, the rootfstype= arguments above
+# will need to be adjusted accordingly.
 
 ### All default-values can be altered via the configfile
 
@@ -183,6 +185,9 @@
 # which must be in uncompressed form. (can not be .gz file)
 LOADNATIONALKEYB=0
 
+# Filesystem type to use in the initrd (minix or ext2)
+INITFSTYPE=minix
+
 # Try to auto-assemble linux software raid md devices. This is only
 # needed and used on USEPIVOT=2 (initramfs/switch_root) type build.
 # This gets automatically disabled if none of needed devices (BOOTDEV,
@@ -887,10 +892,51 @@
         y=`expr ${y} + 1`
     fi
 
+    # Try to detect if the running system lacks support for
+    # the named filesystem, to avoid a less graceful error.
+    if [ -r /proc/filesystems ]; then
+        if ! grep -q "	${INITFSTYPE}\$" /proc/filesystems ; then
+            echo "************************************************"
+            echo "***  INITFSTYPE specifies a filesystem type  ***"
+            echo "***  not supported by the running kernel.    ***"
+            echo "***  Script aborted.                         ***"
+            echo "************************************************"
+            exit 1
+        fi
+    fi
+
+    # Check if the currently booted kernel has a rootfstype=
+    # argument that mismatches; warn but do not abort.
+    if [ -r /proc/cmdline ]; then
+        ROOTFSTYPEARG=$(grep -E -o 'rootfstype=[^ ]+' /proc/cmdline | cut -d= -f2-)
+        if [ -n "${ROOTFSTYPEARG}" ] && [ "${ROOTFSTYPEARG}" != "${INITFSTYPE}" ]; then
+            echo "******************************************************"
+            echo "***  Warning: INITFSTYPE '${INITFSTYPE}'"
+            echo "***  does not match the running kernel argument"
+            echo "***  'rootfstype=${ROOTFSTYPEARG}'"
+            echo "***  Existing bootloader arguments may fail to boot."
+            echo "******************************************************"
+        fi
+    fi
+
+    if [ ${INITFSTYPE} = "minix" ]; then
+        MKFS_ARGS="-t minix -i 32 tmp-i-$$ ${y}"
+    elif [ ${INITFSTYPE} = "ext2" ]; then
+        MKFS_ARGS="-t ext2 -i 1024 tmp-i-$$"
+        y=`expr ${y} + 80`
+    else
+        echo "*******************************************"
+        echo "***  Unsupported INITFSTYPE specified;  ***"
+        echo "***  must be one of: minix, ext2        ***"
+        echo "***  Script aborted.                    ***"
+        echo "*******************************************"
+        exit 1
+    fi
+
     dd if=/dev/zero of=tmp-i-$$ bs=1024 count=${y}
-    /sbin/mkfs -t minix -i 32 tmp-i-$$ ${y}
+    /sbin/mkfs ${MKFS_ARGS}
     ${LOSETUPLIVE} /dev/loop${DEVFSSLASH2}${TEMPLOOPINDEX} tmp-i-$$
-    mount -t minix /dev/loop${DEVFSSLASH2}${TEMPLOOPINDEX} tmp-d-$$
+    mount -t ${INITFSTYPE} /dev/loop${DEVFSSLASH2}${TEMPLOOPINDEX} tmp-d-$$
 fi
 cd tmp-d-$$