I tried to flash. MS-6337 with recently added MS-6178. It was needed to put WP# and TBL# pins to high but since another chip is in use it is ok.
With filo as payload, post card gave 10 ... pause... 80, f8, fe ..short pause and ff. (+ some other codes between them)
So at least ram is ok I think.
With very small kernel as payload post card gave just ff.
I didn't do any modifications to MS6178. Probably some is needed.
Any suggestions?