Historical retained-firmware behavior allows an abbreviated SRM device name only when it identifies one device uniquely. A full designation can include its complete path, such as dka100.1.0.1.8. Ambiguity is most likely when selecting DKA100, DKB100, or DKC100 on a wide controller that also exposes DKA1000, DKB1000, or DKC1000. If BOOT or SET BOOTDEF_DEV reports an ambiguous device, verify the designation before continuing.

Use SHOW DEVICE to identify the intended disk and prefer the complete device designation. The retained-firmware workaround is to add a dot to the shorter unit, for example BOOT DKA100. with the dot as part of the token. If the console does not accept that form, use the complete designation rather than experimenting on a production boot definition.