flash-shelly.py doesn't know to update Plus Plug S (Gen 2) device

[hadess]

Following the instructions for a Shelly Plug Plug S device (Gen 2), the script failed to update to the HomeKit firmware:

$ ./tools/flash-shelly.py -v 5 192.168.1.130
load_security
OS: Linux
app_version: 3.0.0
do_all: False
dry_run: False
quiet_run: False
silent_run: False
timeout: 20
reboot: False
manual_hosts: ['192.168.1.130'] (1)
user: admin
password: None
action: flash
mode: homekit
info_level: 3
fw_type_filter: all
model_type_filter: all
device_name_filter: all
version: 
exclude: 
local_file: 
variant: 
force: False
verbose: 5
hap_setup_code: 
network_type: 
ipv4_ip: 
ipv4_mask: 
ipv4_gw: 
ipv4_dns: 
log_filename: 
[Manual Hosts]
Looking for Shelly devices...

[Manual Hosts] action 192.168.1.130
get_security_data
[Security] 192.168.1.130
[Security] username: admin from commandline
[Security] password: None from commandline
Device: 192.168.1.130 is Online
RESPONSE: <Response [404]>
RESPONSE: <Response [404]>

Host: 192.168.1.130 is not a Shelly device.

Devices found: 0 Upgradeable: 0 Flashed: 0

I tried downgrading the firmware to the stock 1.3.3 (as mentioned in this issue) using the firmware here:
https://rojer.me/files/shelly/stock/

But the plug seemed to revert back to 1.4.4 after less than a minute (I'm guessing because something didn't work in 1.3.3 and it reverted to its backup firmware?).

Going to http://X.X.X.X/ota?url=http://shelly.rojer.cloud/update in a browser worked.

[markirb]

The flash tool is not well maintained at the moment.... I will have a look when I find time.