Some error messages appear in the tce-bootload log (python script that loads the extensions on boot):
OS Error code libn:4352
Successful Retry on libn
OS Error code flwm:4352
Successful Retry on flwm
OS Error code xz.t:4352
Successful Retry on xz.t
OS Error code icu.:4352
OS Error code cair:4352
OS Error code icu.:4352
Successful Retry on cair
OS Error code libe:4352
OS Error code dbus:4352
Successful Retry on icu.
Successful Retry on dbus
Successful Retry on libe
...
1) a minor problem: the name of the extension is cut off. The problem is that in the call to mount_extension the second parameter should be p[:-4]:
mount_extension('sudo /usr/bin/mount -t squashfs -o loop ' + sys.argv[1] + '/optional/' + p + ' ' + root + '/tmp/tcloop/' + p[:-4], p[-:4])
2) and the main thing: why the 4352 errors occur and what do they mean? Then the extension mounting is retried and performed successfully.