Reviving a four year old reMarkable 2

I discovered my reMarkable 2 paper tablet from 2021, which had been untouched for around four years. The tablet was in a poor condition. To potentially bring it back to working order, I followed a solution shared on a forum. I connected to the tablet via SSH, adjusted the clock, and downloaded a software update. After the initial update, I encountered an HTTP 400 error.

Furthermore, the cloud sync reported that my outdated system version could not be accepted. The error message stated, "Unable to sync. Please update this application to continue using the reMarkable cloud." Following the first update, the tablet's software version was upgraded to 3.11.2.5, but further updates were not possible. From the system log (journalctl for swupdate.service), it appeared that the update started before the Wi-Fi/DNS was operational, resulting in a host name resolution failure.

Restarting the update services restored the Settings screen to offer version 3.27.3.0, and a subsequent update brought the tablet up to the latest available software version. However, starting with version 3.22, SSH over Wi-Fi was disabled by default, causing the LAN port 22 to refuse connections. To access the tablet via SSH, I utilized the USB port (e.g., 10.11.99.1) instead.

Unfortunately, cloud sync continued to be problematic; it failed to retrieve any newly uploaded files. Instead of further investigating the cloud sync issue, I turned on the tablet's optional web server to facilitate file uploads and exports. Before making these changes, I made a backup of the xochitl config file, toggling WebInterfaceEnabled to true.