83Plus:BCALLs:8063

Synopsis

Unofficial Name: CheckHeaderKey

BCALL Address: 8063

Check if a given key (specified by an app or OS header) is present on the calculator.

Inputs

• appData contains the app header

Outputs

• Z if the key specified is present, either as a built-in (freeware) key or in the certificate.

Destroys

• AF, BC, DE, HL
• OP1, ramCode, appID

Comments

Flash must be write-enabled first if you want to check for non-built-in keys.

On the 84+, this routine does not accept the built-in 04 key as valid (even though SetupOSPubKey will happily load it if requested.) Thus, in order for the calculator to accept an 04-signed OS, the 04 key must actually be present in the certificate. This seems to be a bug, though a convenient one for TI.