diff --git a/debian.cfg b/debian.cfg
index 0d1365d..339f30d 100644
--- a/debian.cfg
+++ b/debian.cfg
@@ -123,7 +123,7 @@ d-i preseed/early_command string true; \
 # efi 分区大小未改变时，不会被格式化，因此需要手动删除旧系统的 efi 文件
 # os-prober 卡太久，因此跳过
 d-i partman/early_command string true; \
-    confhome="$(grep -o 'extra\.confhome=[^ ]*' /proc/cmdline | cut -d= -f2)"; \
+    confhome="$(grep -o 'extra_confhome=[^ ]*' /proc/cmdline | cut -d= -f2)"; \
 
     postinst=/var/lib/dpkg/info/bootstrap-base.postinst; \
     cp $postinst $postinst.orig; \
@@ -161,7 +161,7 @@ d-i partman/early_command string true; \
 # 另一种方法处理 cloudcone
 # if [ "$link_grub_dir" = 1 ]; then mkdir /target/boot/grub2; echo 'chainloader (hd0)+1' >/target/boot/grub2/grub.cfg; fi; \
 d-i preseed/late_command string true; \
-    link_grub_dir="$(grep -o 'extra\.link_grub_dir=[^ ]*' /proc/cmdline | cut -d= -f2)"; \
+    link_grub_dir="$(grep -o 'extra_link_grub_dir=[^ ]*' /proc/cmdline | cut -d= -f2)"; \
     if [ "$link_grub_dir" = 1 ]; then ln -s grub /target/boot/grub2; fi; \
 
     in-target systemctl enable ssh; \
diff --git a/get-xda.sh b/get-xda.sh
index 1124d27..6da568d 100644
--- a/get-xda.sh
+++ b/get-xda.sh
@@ -10,7 +10,7 @@ get_all_disks() {
 get_xda() {
     # 如果没找到 main_disk 或 xda
     # 返回假的值，防止意外地格式化全部盘
-    main_disk="$(grep -o 'extra\.main_disk=[^ ]*' /proc/cmdline | cut -d= -f2)"
+    main_disk="$(grep -o 'extra_main_disk=[^ ]*' /proc/cmdline | cut -d= -f2)"
 
     if [ -z "$main_disk" ]; then
         echo 'MAIN_DISK_NOT_FOUND'
diff --git a/redhat.cfg b/redhat.cfg
index 9a50590..307fa8f 100644
--- a/redhat.cfg
+++ b/redhat.cfg
@@ -38,10 +38,10 @@ distro=$(awk -F: '{ print $3 }' </etc/system-release-cpe)
 releasever=$(awk -F: '{ print $5 }' </etc/system-release-cpe)
 
 # 重新整理 extra，grub把两侧的引号吃掉了，eval出错，要重新添加引号
-# 提取 extra.confhome extra.mirrorlist extra.main_disk
+# 提取 extra_confhome extra_mirrorlist extra_main_disk
 prefix=extra
-for var in $(grep -o "\b$prefix\.[^ ]*" /proc/cmdline | xargs); do
-    eval "$(echo "$var" | sed -E "s/$prefix\.([^=]*)=(.*)/\1='\2'/")"
+for var in $(grep -o "\b${prefix}_[^ ]*" /proc/cmdline | xargs); do
+    eval "$(echo "$var" | sed -E "s/${prefix}_([^=]*)=(.*)/\1='\2'/")"
 done
 
 # centos7 证书链未更新，需要 --no-check-certificate
@@ -151,10 +151,10 @@ fi
 
 # 分步安装的系统，要将最后一个分区（installer）合并到系统分区
 if [ -e /dev/disk/by-label/installer ]; then
-    # 提取 extra.localtest extra.confhome extra.mirrorlist
+    # 提取 extra_localtest extra_confhome extra_mirrorlist
     prefix=extra
-    for var in $(grep -o "\b$prefix\.[^ ]*" /proc/cmdline | xargs); do
-        eval "$(echo "$var" | sed -E "s/$prefix\.([^=]*)=(.*)/\1='\2'/")"
+    for var in $(grep -o "\b${prefix}_[^ ]*" /proc/cmdline | xargs); do
+        eval "$(echo "$var" | sed -E "s/${prefix}_([^=]*)=(.*)/\1='\2'/")"
     done
 
     cd /
diff --git a/reinstall.sh b/reinstall.sh
index 82d6cbc..18d70cc 100644
--- a/reinstall.sh
+++ b/reinstall.sh
@@ -2069,30 +2069,35 @@ build_finalos_cmdline() {
             value=${!key}
             key=${key#finalos_}
             if [ -n "$value" ] && [ $key != "mirrorlist" ]; then
-                finalos_cmdline+=" finalos.$key='$value'"
+                finalos_cmdline+=" finalos_$key='$value'"
             fi
         done
     fi
 }
 
 build_extra_cmdline() {
+    # 使用 extra_xxx=yyy 而不是 extra.xxx=yyy
+    # 因为 debian installer /lib/debian-installer-startup.d/S02module-params
+    # 会将 extra.xxx=yyy 写入新系统的 /etc/modprobe.d/local.conf
+    # https://answers.launchpad.net/ubuntu/+question/249456
+    # https://salsa.debian.org/installer-team/rootskel/-/blob/master/src/lib/debian-installer-startup.d/S02module-params?ref_type=heads
     for key in confhome hold force cloud_image main_disk; do
         value=${!key}
         if [ -n "$value" ]; then
-            extra_cmdline+=" extra.$key='$value'"
+            extra_cmdline+=" extra_$key='$value'"
         fi
     done
 
     # 指定最终安装系统的 mirrorlist，链接有&，在grub中是特殊字符，所以要加引号
     if [ -n "$finalos_mirrorlist" ]; then
-        extra_cmdline+=" extra.mirrorlist='$finalos_mirrorlist'"
+        extra_cmdline+=" extra_mirrorlist='$finalos_mirrorlist'"
     elif [ -n "$nextos_mirrorlist" ]; then
-        extra_cmdline+=" extra.mirrorlist='$nextos_mirrorlist'"
+        extra_cmdline+=" extra_mirrorlist='$nextos_mirrorlist'"
     fi
 
     # cloudcone 特殊处理
     if is_grub_dir_linked; then
-        finalos_cmdline+=" extra.link_grub_dir=1"
+        finalos_cmdline+=" extra_link_grub_dir=1"
     fi
 }
 
diff --git a/trans.sh b/trans.sh
index fa6a8e9..9b1cce1 100644
--- a/trans.sh
+++ b/trans.sh
@@ -322,7 +322,7 @@ extract_env_from_cmdline() {
                 value=$(echo $line | cut -d= -f2-)
                 eval "$key='$value'"
             fi
-        done < <(xargs -n1 </proc/cmdline | grep "^$prefix" | sed "s/^$prefix\.//")
+        done < <(xargs -n1 </proc/cmdline | grep "^${prefix}_" | sed "s/^${prefix}_//")
     done
 }
 
@@ -3556,13 +3556,13 @@ install_redhat_ubuntu() {
 
     # 重新整理 extra，因为grub会处理掉引号，要重新添加引号
     extra_cmdline=''
-    for var in $(grep -o '\bextra\.[^ ]*' /proc/cmdline | xargs); do
-        if [[ "$var" = "extra.main_disk="* ]]; then
+    for var in $(grep -o '\bextra_[^ ]*' /proc/cmdline | xargs); do
+        if [[ "$var" = "extra_main_disk="* ]]; then
             # 重新记录主硬盘
             refind_main_disk
-            extra_cmdline="$extra_cmdline extra.main_disk=$main_disk"
+            extra_cmdline="$extra_cmdline extra_main_disk=$main_disk"
         else
-            extra_cmdline="$extra_cmdline $(echo $var | sed -E "s/(extra\.[^=]*)=(.*)/\1='\2'/")"
+            extra_cmdline="$extra_cmdline $(echo $var | sed -E "s/(extra_[^=]*)=(.*)/\1='\2'/")"
         fi
     done
 
@@ -3588,7 +3588,7 @@ install_redhat_ubuntu() {
             insmod all_video
             search --no-floppy --label --set=root installer
             loopback loop /ubuntu.iso
-            linux (loop)/casper/vmlinuz iso-scan/filename=/ubuntu.iso autoinstall noprompt noeject cloud-config-url=$ks $extra_cmdline extra.kernel=$kernel --- $console_cmdline
+            linux (loop)/casper/vmlinuz iso-scan/filename=/ubuntu.iso autoinstall noprompt noeject cloud-config-url=$ks $extra_cmdline extra_kernel=$kernel --- $console_cmdline
             initrd (loop)/casper/initrd
         }
 EOF
diff --git a/ubuntu.yaml b/ubuntu.yaml
index 2f331b4..d0597d5 100644
--- a/ubuntu.yaml
+++ b/ubuntu.yaml
@@ -20,10 +20,10 @@ autoinstall:
       # https://askubuntu.com/questions/1302392/ubuntu-server-20-04-setup-stuck-at-block-probing-did-not-discover-any-disks
       mount | grep /isodevice && { losetup -d /dev/loop0; umount -l /isodevice; } || true
 
-      # 提取 extra.confhome extra.kernel
+      # 提取 extra_confhome extra_kernel
       prefix=extra
-      for var in $(grep -o "\b$prefix\.[^ ]*" /proc/cmdline | xargs); do
-          eval "$(echo $var | sed -E "s/$prefix\.([^=]*)=(.*)/\1='\2'/")"
+      for var in $(grep -o "\b${prefix}_[^ ]*" /proc/cmdline | xargs); do
+          eval "$(echo $var | sed -E "s/${prefix}_([^=]*)=(.*)/\1='\2'/")"
       done
 
       # 生成分区信息
@@ -49,10 +49,10 @@ autoinstall:
       # 还原 DNS
       # sed -i -E 's/^#(nameserver )/\1/' /etc/resolv.conf
 
-      # 提取 extra.confhome
+      # 提取 extra_confhome
       prefix=extra
-      for var in $(grep -o "\b$prefix\.[^ ]*" /proc/cmdline | xargs); do
-          eval "$(echo $var | sed -E "s/$prefix\.([^=]*)=(.*)/\1='\2'/")"
+      for var in $(grep -o "\b${prefix}_[^ ]*" /proc/cmdline | xargs); do
+          eval "$(echo $var | sed -E "s/${prefix}_([^=]*)=(.*)/\1='\2'/")"
       done
 
       # 下载合并分区脚本