--- doc/build/debian12_install.frag	2024/06/15 17:43:13	1.1
+++ doc/build/debian12_install.frag	2024/06/20 01:29:16	1.2
@@ -100,12 +100,11 @@ Use ufw to allow incoming traffic for th
 ssh, www, https
 </p>
 <p>Check if ufw is installed</p>
-<pre>sudo dpkg-query -s gpg |grep Status</pre>
+<pre>sudo dpkg-query -s ufw |grep Status</pre>
 <p>If the result is not: <i>Status: install ok installed</i>, then install it:
 <pre>sudo apt-get install ufw</pre>
 <p>Configure ufw by executing the following:</p>
 <pre>
-sudo apt-get install ufw
 sudo ufw default deny
 sudo ufw enable
 sudo ufw allow ssh
@@ -136,6 +135,8 @@ sudo systemctl stop systemd-timesyncd
 sudo systemctl disable systemd-timesyncd
 sudo apt-get remove systemd-timesyncd
 sudo apt-get install chrony
+sudo systemctl start chrony
+sudo systemctl enable chrony
 </pre>
 <h2>4. <a name="upd">Update your system</a></h2>
 <p>
@@ -152,12 +153,20 @@ If kernel packages were updated, reboot
 <h3>Import the LON-CAPA encryption key</h3>
 <p>Check if gpg is installed</p>
 <pre>sudo dpkg-query -s gpg |grep Status</pre>
-<p>If the result is not: <i>Status: install ok installed</i>, then install it:
+<p>If the result is not: <i>Status: install ok installed</i>, then install it:</p>
 <pre>sudo apt-get install gpg</pre>
 <p>Check if wget is installed</p>
 <pre>sudo dpkg-query -s wget |grep Status</pre>
-<p>If the result is not: <i>Status: install ok installed</i>, then install it:
+<p>If the result is not: <i>Status: install ok installed</i>, then install it:</p>
 <pre>sudo apt-get install wget</pre>
+<p>Check if /etc/apt/keyrings directory exists by executing:</p>
+<pre>
+ls -al /etc/apt/keyrings
+</pre>
+<p>If it is missing, create it by executing:</p>
+<pre>
+sudo mkdir /etc/apt/keyrings 
+</pre>
 <p> Execute: </p>
 <pre>
 wget -q -O - https://install.loncapa.org/versions/debian/APT-GPG-KEY-loncapa.asc | gpg --dearmor | sudo tee /etc/apt/keyrings/loncapa.gpg > /dev/null
@@ -182,6 +191,7 @@ deb http://deb.debian.org bookworm-updat
 <h3>Install prerequisites</h3>
 <p> Execute: </p>
 <pre>
+sudo apt-get update
 sudo apt-get install loncapa-prerequisites
 </pre><p>
 This may take some minutes due to LON-CAPA's large number of dependencies.