Not used to H2xxx tools and their syntax. But I wonder where 0x5BC35 and 0x7769A come from? I did once use dumpstore and setvar (link)
A variable store normally is referenced by GUID and the variable by its position, here possibly A04A27F4-DF00-4D42-B552-39511302113D for the GUID, the variable would be 0x17F
And I’d try to dump the store first and to check if 0x17F really is 0xF before trying to write.
(One way you’re right, you’re almost bricked anyway, but on the other hand changing something relevant in the wrong place could lead to some extra work when working on the dump)