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Old 03-12-2016, 11:36 AM   #3
knc1
Going Viral
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Posts: 17,212
Karma: 18210809
Join Date: Feb 2012
Location: Central Texas
Device: No K1, PW2, KV, KOA
Checking the installed kdb utility

A temporary work-around to having the database in a read-only file system type.

Make a directory in writable file space:
Code:
[root@kindle root]# mkdir kdb
[root@kindle root]# cd kdb
[root@kindle kdb]# cp -a /etc/kdb.src/* .
[root@kindle kdb]# pwd
/tmp/root/kdb
[root@kindle kdb]# cd ..
Over-mount the cramfs mount point:
Code:
[root@kindle root]# mount --bind /tmp/root/kdb /etc/kdb.src
[root@kindle root]# df /etc/kdb.src
Filesystem           1K-blocks      Used Available Use% Mounted on
tmpfs                    32768      1740     31028   5% /var
Now play with making changes to the OTA update settings:
Code:
[root@kindle root]# kdb get system/daemon/otaup/TRANSFER_TIMEOUT_SEC
126000
[root@kindle root]# kdb set system/daemon/otaup/TRANSFER_TIMEOUT_SEC 60
[root@kindle root]# kdb get system/daemon/otaup/TRANSFER_TIMEOUT_SEC
60
Since the 'bind mount' isn't in /etc/fstab - it will go-away on a re-boot.
The writable copy of the database is in tmpfs - it will also go-away on a re-boot.
Which gives a bit of protection from bricking the Kindle (push the power button to recover).

And when happy with the changes, we can create a replacement cramfs image:
Code:
[root@kindle root]# mkcramfs
usage: mkcramfs [-h] [-e edition] [-i file] [-n name] dirname outfile
 -h         print this help
 -E         make all warnings errors (non-zero exit status)
 -e edition set edition number (part of fsid)
 -i file    insert a file image into the filesystem (requires >= 2.4.0)
 -n name    set name of cramfs filesystem
 -p         pad by 512 bytes for boot code
 -s         sort directory entries (old option, ignored)
 -v         be more verbose
 -z         make explicit holes (requires >= 2.3.39)
 dirname    root of the directory tree to be compressed
 outfile    output file
Isn't it nice that Lab126 provides utilities that have no reason for being on the system?

Last edited by knc1; 03-12-2016 at 11:41 AM.
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