Jim Cramer "doesn't trust" the semiconductor stocks despite two upgrades Friday, he said on CNBC's "Stop Trading!" segment.

Cramer said glut talk from big memory chipmaker Micron ( MU - Get Report) points up the futility of trying to buy tech out of season. Cramer said it's unwise to buy tech stocks till the latter end of the year, because of the way Wall Street works. Thus he said he's not surprised to see Micron down 3% and the SOX index of chip stocks down 1.2% even in the wake of upgrades from JPMorgan and Deutsche Bank.

Cramer said he could "make a case" for buying Broadcom ( BRCM), given how far the stock has fallen, and he owns Marvell ( MRVL - Get Report) for his charitable trust. But he said those plays are strictly long-term holdings, based on how poor results have been and the seemingly low risk that they can get any worse.

Cramer doesn't like gas driller Chesapeake ( CHK - Get Report), saying it's "not my cup of tea" because management has "financed the heck out of it." Cramer said while Chesapeake goes from $29 to $29 to $29, Marathon Oil ( MRO - Get Report) is moving ahead.

Cramer also said the rally in Agco ( AG - Get Report) shows that the bull case on ethanol and agriculture can overcome even the most pathetic, quarter-missing fundamentals.

At the time of publication, Cramer was long Marvell.

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