linux

Writing /system on an unrooted MT6592 handheld from Linux. BROM port-open fails because new cdc_acm rejects TIOCCBRK; Download refuses with "PMT changed". Use SP Flash Tool v5.1648, an LD_PRELOAD shim, Preloader mode and write-memory at the physical address.

Template units whose EnvironmentFile and user had been deleted restart-looped every 3 s for 73 days (1,958,017 restarts each). systemd fails before spawning a process, so CPU and ps show nothing, and RestartSec=3 stays under the start limit. Find them by NRestarts; vacuum the journal by size.

claude auth login completes in the browser, then Claude Code says it is not logged in and gives up after a few retries. ~/.claude was owned by root after claude had once been run as root with the user's HOME, so the token file could not be written. chown the directory back to the user.

A default ACL granting a backup user read access worked, then broke after certbot issued a key or Home Assistant rewrote .storage/auth. Files created with mode 0600 get an ACL mask of ---, so the inherited entry shows #effective:---. Re-running setfacl -m recomputes the mask; run it from cron before each backup.

After a kernel and NVIDIA driver upgrade without a reboot, restarting X gave a black screen and "Failed to initialize the NVIDIA kernel module". The running kernel had only the old module loaded. Build the module for the running kernel with DKMS, swap the modules, recreate /dev/dri, then reboot properly.

A systemd user service was inactive after every boot. The journal showed default.target "Found ordering cycle" and deleted its start job. A dependency was WantedBy=default.target and also After=default.target; removing the After= line fixed it.

Trace Bitmap silently did nothing on an image already embedded in an Inkscape 0.92 document. Opening the image fresh in its own window, tracing there, and pasting the path back worked.