i attached script with ALTER there https://forum.team-mediaportal.com/threads/use-innodb-as-mysql-engine.114397/page-4#post-941725 (in case anyone wants to test this) - that was proved as working by many people
innodb_large_prefix
Introduced5.6.3
Command-Line Format--innodb_large_prefix
Option-File Formatinnodb_large_prefix
System Variable Nameinnodb_large_prefix
Variable ScopeGlobal
Dynamic VariableYes
Permitted Values
Typeboolean
DefaultOFF
Enable this option to allow index key prefixes longer than 767 bytes (up to 3072 bytes), for InnoDB tables that use the DYNAMIC and COMPRESSED row formats. (Creating such tables also requires the option values innodb_file_format=barracuda and innodb_file_per_table=true.) See Section 14.2.7, “Limits on InnoDB Tables” for the relevant maximums associated with index key prefixes under various settings.
For tables using the REDUNDANT and COMPACT row formats, this option does not affect the allowed key prefix length. It does introduce a new error possibility. When this setting is enabled, attempting to create an index prefix with a key length greater than 3072 for a REDUNDANT or COMPACT table causes an error ER_INDEX_COLUMN_TOO_LONG (1727).