What value could I insert into a bit type column?

Generally speaking, for boolean or bit data types, you would use 0 or 1 like so:

UPDATE tbl SET bitCol = 1 WHERE bitCol = 0

See also:

mysql sql boolean bit

If you're using SQL Server, you can set the value of bit fields with 0 and 1

'true' and 'false' (yes, using strings)

...your_bit_field='false'... => equivalent to 0

mysql sql boolean bit

Your issue is in PHPMyAdmin itself. Some versions do not display the value of bit columns, even though you did set it correctly.

CodeHunter