Lenovo T99W175 / Foxconn SDX55 update on LVFS breaks FCC unlock

[Bjørn Mork]

Bjørn Mork <bjorn at mork.no> writes:

> Wrt the implementation: Any protocol depending on closed binaries is
> broken by design, without exception.  It doesn't matter whether you use
> a "secret" algorithm or just store keys inside the binary. Anything that
> was compiled can be decompiled.  Sure it can be obfuscated to make that
> harder.  We all love a challenge :-)

And just let me prove that fact without even modifying one byte of the
code:

 root at miraculix:/tmp# cat /sys/class/dmi/id/product_family
 ThinkPad X1 Carbon 4th
 root at miraculix:/tmp# echo ThinkEdge > /tmp/product_family
 root at miraculix:/tmp# mount --bind /tmp/product_family /sys/class/dmi/id/product_family
 root at miraculix:/tmp# cat /sys/class/dmi/id/product_family
 ThinkEdge

And what do you think?  There goes the machine check....

 May  1 18:24:59 miraculix DPR_Fcc_unlock_service: main(): FCC unlock app started
 May  1 18:24:59 miraculix DPR_Fcc_unlock_service: get_product(): DT
 May  1 18:24:59 miraculix DPR_Fcc_unlock_service: MACHINE = [4] --- THINKEDGE_SE30 = [4]
 May  1 18:24:59 miraculix DPR_Fcc_unlock_service: main(): FCC unlock app exited

This doesn't work for me of course, only having the original EM7455
modem.  But I do note that the log output changed from -1 to 4, whatever
that means.  Previously:

 May  1 18:21:01 miraculix DPR_Fcc_unlock_service: MACHINE = [-1] --- THINKEDGE_SE30 = [4]

Something to try out on your X1E4, maybe?


Bjørn