Let's Encrypt fix for webOS. Tested on 3.8 only, put this into /var/lib/webosbrew/init.d and you should be probably done.

50-customca

#!/bin/sh

# Directory to store overlays in (one directory structure is created per overlay configured down below)
OVERLAY_BASE=/var/lib/webosbrew/customca

overlay() {
        set -e
        overlay_id="$(echo $1 | sed 's;/;__;g')"
        unset TARGET SOURCE FSTYPE OPTIONS
        eval $(findmnt -P $1)
        if [[ "$FSTYPE" == "overlay" ]] || [ -f "$1" ] && [[ "$FSTYPE" != "" ]]; then
                echo "[-] Overlay '$1' already mounted"
        elif [ -f "$1" ]; then
		if [ ! -f "$OVERLAY_BASE/$overlay_id" ]; then
			echo "[ ] Preparing overlay for '$1'"
			cp $1 $OVERLAY_BASE/$overlay_id;
		fi
		mount --bind "$OVERLAY_BASE/$overlay_id" "$1"
		echo "[+] File overlay '$1' mounted"
	else
                echo "[ ] Preparing overlay for '$1' -> $OVERLAY_BASE/$overlay_id"
                mkdir -p "$OVERLAY_BASE/$overlay_id/upper" "$OVERLAY_BASE/$overlay_id/work"
                mount -t overlay -o lowerdir=$1,upperdir=$OVERLAY_BASE/$overlay_id/upper/,workdir=$OVERLAY_BASE/$overlay_id/work/ overlay-$overlay_id $1
                echo "[+] Overlay '$1' mounted"
	fi
}

# Usage:
overlay /etc/ssl/certs
overlay /usr/share/ca-certificates
overlay /etc/ca-certificates.conf
overlay /etc/pki

if [ ! -f "/usr/share/ca-certificates/mozilla/ISRG_Root_X1.crt" ]; then
  # from https://letsencrypt.org/certs/isrgrootx1.pem
  cat <<EOF >"/usr/share/ca-certificates/mozilla/ISRG_Root_X1.crt"
-----BEGIN CERTIFICATE-----
MIIFazCCA1OgAwIBAgIRAIIQz7DSQONZRGPgu2OCiwAwDQYJKoZIhvcNAQELBQAw
TzELMAkGA1UEBhMCVVMxKTAnBgNVBAoTIEludGVybmV0IFNlY3VyaXR5IFJlc2Vh
cmNoIEdyb3VwMRUwEwYDVQQDEwxJU1JHIFJvb3QgWDEwHhcNMTUwNjA0MTEwNDM4
WhcNMzUwNjA0MTEwNDM4WjBPMQswCQYDVQQGEwJVUzEpMCcGA1UEChMgSW50ZXJu
ZXQgU2VjdXJpdHkgUmVzZWFyY2ggR3JvdXAxFTATBgNVBAMTDElTUkcgUm9vdCBY
MTCCAiIwDQYJKoZIhvcNAQEBBQADggIPADCCAgoCggIBAK3oJHP0FDfzm54rVygc
h77ct984kIxuPOZXoHj3dcKi/vVqbvYATyjb3miGbESTtrFj/RQSa78f0uoxmyF+
0TM8ukj13Xnfs7j/EvEhmkvBioZxaUpmZmyPfjxwv60pIgbz5MDmgK7iS4+3mX6U
A5/TR5d8mUgjU+g4rk8Kb4Mu0UlXjIB0ttov0DiNewNwIRt18jA8+o+u3dpjq+sW
T8KOEUt+zwvo/7V3LvSye0rgTBIlDHCNAymg4VMk7BPZ7hm/ELNKjD+Jo2FR3qyH
B5T0Y3HsLuJvW5iB4YlcNHlsdu87kGJ55tukmi8mxdAQ4Q7e2RCOFvu396j3x+UC
B5iPNgiV5+I3lg02dZ77DnKxHZu8A/lJBdiB3QW0KtZB6awBdpUKD9jf1b0SHzUv
KBds0pjBqAlkd25HN7rOrFleaJ1/ctaJxQZBKT5ZPt0m9STJEadao0xAH0ahmbWn
OlFuhjuefXKnEgV4We0+UXgVCwOPjdAvBbI+e0ocS3MFEvzG6uBQE3xDk3SzynTn
jh8BCNAw1FtxNrQHusEwMFxIt4I7mKZ9YIqioymCzLq9gwQbooMDQaHWBfEbwrbw
qHyGO0aoSCqI3Haadr8faqU9GY/rOPNk3sgrDQoo//fb4hVC1CLQJ13hef4Y53CI
rU7m2Ys6xt0nUW7/vGT1M0NPAgMBAAGjQjBAMA4GA1UdDwEB/wQEAwIBBjAPBgNV
HRMBAf8EBTADAQH/MB0GA1UdDgQWBBR5tFnme7bl5AFzgAiIyBpY9umbbjANBgkq
hkiG9w0BAQsFAAOCAgEAVR9YqbyyqFDQDLHYGmkgJykIrGF1XIpu+ILlaS/V9lZL
ubhzEFnTIZd+50xx+7LSYK05qAvqFyFWhfFQDlnrzuBZ6brJFe+GnY+EgPbk6ZGQ
3BebYhtF8GaV0nxvwuo77x/Py9auJ/GpsMiu/X1+mvoiBOv/2X/qkSsisRcOj/KK
NFtY2PwByVS5uCbMiogziUwthDyC3+6WVwW6LLv3xLfHTjuCvjHIInNzktHCgKQ5
ORAzI4JMPJ+GslWYHb4phowim57iaztXOoJwTdwJx4nLCgdNbOhdjsnvzqvHu7Ur
TkXWStAmzOVyyghqpZXjFaH3pO3JLF+l+/+sKAIuvtd7u+Nxe5AW0wdeRlN8NwdC
jNPElpzVmbUq4JUagEiuTDkHzsxHpFKVK7q4+63SM1N95R1NbdWhscdCb+ZAJzVc
oyi3B43njTOQ5yOf+1CceWxG1bQVs5ZufpsMljq4Ui0/1lvh+wjChP4kqKOJ2qxq
4RgqsahDYVvTH9w7jXbyLeiNdd8XM2w9U/t7y0Ff/9yi0GE44Za4rF2LN9d11TPA
mRGunUHBcnWEvgJBQl9nJEiU0Zsnvgc/ubhPgXRR4Xq37Z0j4r7g1SgEEzwxA57d
emyPxgcYxn/eR44/KJ4EBs+lVDR3veyJm+kXQ99b21/+jh5Xos1AnX5iItreGCc=
-----END CERTIFICATE-----
EOF
  ln -sf /usr/share/ca-certificates/mozilla/ISRG_Root_X1.crt /etc/ssl/certs/ISRG_Root_X1.crt
fi

if grep -i DST_Root_CA_X3 /etc/ca-certificates.conf; then
  echo "[+] Removing DST_Root_CA_X3"
  sed '/DST_Root_CA_X3/d' /etc/ca-certificates.conf > /tmp/c && cp /tmp/c /etc/ca-certificates.conf
fi

if ! grep 'ISRG_Root_X1' /etc/ca-certificates.conf; then
  echo "[+] Adding ISRG_Root_X1"
  echo 'mozilla/ISRG_Root_X1.crt' >> /etc/ca-certificates.conf
fi

if [[ "$(ls -td /etc/ssl/certs/* /etc/ca-certificates.conf | head -1)" != "/etc/ssl/certs/ca-certificates.crt" ]]; then
  update-ca-certificates
  c_rehash
  cp /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/trusted_cas.crt 
fi

# TODO: certutil -d /etc/pki/nssdb/ -A -t 'C,,' -n CA -i /usr/share/ca-certificates/...

@Informatic
Hello! I can confitm it works on WebOS 4.9. Thank you very much!

But is there a way to make writable the inital root directory "/" ?
I tried overlay / but it shows:
[-] Overlay '/' already mounted

I need to create /opt ...

Thank you!

Hi @Informatic,

Now that my webOS 3.4.0 TV has been rooted I would like to do something about the web browser, if possible.
Tried the above overlay script to see what it would do, but I get errors on a few pages that used to load and no response on others, so I'm guessing it's not the best fit for my older webOS.
Can it be modified to work, or is something completely different required for webOS <3.5?
I am happy to try out things and provide feedback as necessary.
Thanks.