These come packaged in QFP44 and custom-marked; most likely, this is mask-programmed TMP86CH06U – note the CH06U part in package marking.

Package

With Toshiba logo:

E250013256
CH06U-4UE4
JAPAN 0277 HAL
960061

Without Toshiba logo:

75076365_V35
CH06U-4H15
JAPAN 0252 HAL
492823

Die

(M) (C) 1997 TOSHIBA
EL10

In another place:

ROM-